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Full text of "Evaluation of on-farm agricultural management alternatives"

SJVDP LIBRARY. 



EVALUATION OF ON-FARM 

AGRICULTURAL MANAGEMENT 

ALTERNATIVES 



Prepared for the 

San Joaquin Valley Drainage Program 

Under 
U.S. Bureau of Reclamation Contract 

By 
Boyle Engineering Corporation 



OCTOBER 1986 



This report presents the results of a study undertaken to 
identify and evaluate on-farm agricultural nanagement prac- 
tices that could be used to reduce subsurface drainage flows 
and/or to iitprove drainage water quality. The study was 
funded by the U.S. Bureau of Reclairation as part of the 
Federal-State Interagency San Joaquin Valley Drainage Program. 
Publication of the findings, conclusions, and recommendations 
herein should not be construed as representing the concurrence 
of either the Bureau of Reclamation or any other Federal or 
State agency participating in the Drainage Program. Also, 
mention of trade names or comnercial products does not consti- 
tute endorsement or recommendation by the agencies. The pur- 
pose of this report is to provide the Drainage Program 
agencies with information and alternatives for further con- 
sideration . 



The San Joaquin Valley Drainage Program was established in mid-1984 
and is a cooperative effort of the U.S. Bureau of Reclamation, U.S. Fish 
and Wildlife Service, U.S. Geological Survey, California Department of 
Fish and Game, and California Department of Water Resources. The 
purposes of the Program are to investigate the problems associated with 
the drainage of agricultural lands in the San Joaquin Valley and to 
develop solutions to those problems. Consistent with these purposes. 
Program objectives address the following key areas: (1) Public health, 
(2) surface- and ground-water resources, (3) agricultural productivity, 
and (4) fish and wildlife resources. 

Inquiries concerning the San Joaquin Valley Drainage Program may be 
directed to: 

San Joaquin Valley Drainage Program 
Federal-State Interagency Study Team 
2800 Cottage Way, Rocxn W-2143 
Sacramento, California 95825-1898 



EVALUATIGSI OF ON-FARM 
AGRICULTURAL MANAGEMENT ALTERNATIVES 



Prepared for the 

San Joaquin Valley Drainage Program 
2800 Cottage Way, Rocxn W-2143 
Sacramento, CA 95825-1898 



Under 

U.S. Bureau of Reclamation 

Contract No. 5-CS-20-03270 

Delivery Order No. 6-PD-20-00730 



By 

Boyle Engineering Corporation 

1300 E. Shaw, Suite 176 

Fresno, CA 93710 



October 1986 



TABLE OF CONTENTS 

Page 

SECTION 1 EXECUTIVE SUMMARY 1-1 

SECTION 2 INTRODUCTION 

2.1 Statement of the Problem 2-1 

2.2 Study Objectives 2-3 

2.3 Study Approach and Scope of Work 2-5 

2.3.1 Review Existing Published/Unpublished 
Literature and Research Data Including 
On-Going Research 2-7 

2.3.2 Conduct Field Interviews 2-8 

2.3.3 Identify Existing Agricultural 
Management Practices 2-8 

2.3.4 Identify Feasible On-Farm Agricultural 
Drainage Management Alternatives 2-8 

2.3.5 Determine Field/Laboratory Research 
Program Requirements 2-9 

2.3.5 Prepare Final Report 2-9 
SECTION 3 CBARACTERISTICS OF THE PROJECT AREA 

3.1 Location of Study Area 3-1 

3.2 Environmental Setting 3-6 

3.2.1 Physiographic Setting 3-5 

3.2.2 Geology and Hydrology 3-6 

3.2.3 Climate 3-8 

3.2.4 Soils and Vegetation 3-9 

3.3 Agricultural Setting 3-9 
3.3.1 Irrigated Acreage 3-10 



3.4 Water Conditions 3-10 

3.4.1 Hydrologic Balance 3-10 

3.4.2 San Joaquin Valley Groundwater Studies 3-14 

3.4.3 On-Farm Water Balance 3-19 

3.4.4 Salt Balance 3-22 

3.4.5 Drainage Water Quality 3-24 

3.5 Historical Perspective 3-25 

3.5.1 Early Development of Irrigation 
Facilities in the San Joaquin Valley 3-25 

3.5.2 Development of State and Federal 

Water Projects 3-25 

3.5.3 Development of Drainage Facilities in 

the San Joaquin Valley 3-27 

3.5.4 The San Joaquin Valley Drainage Advisory 
Group 3-28 

3.5.5 The San Joaquin Valley Interagency 
Drainage Program 3-28 

SECTION 4 EXISTING ON-FARM MANAGEMENT PRACTICES 

4.1 General 4-1 

4.2 Cultural Practices 4-1 

4.3 Irrigation Management Practices 4-3 

4.4 Salinity and Drainage Management 4-7 

4.5 Net Economic Return from Crop Production 4-9 

4.6 Existing Irrigation and Drainage Management 
Program 4-10 

4.6.1 The Irrigation Management Service 

(USBR) 4-11 

4.6.2 Irrigation Management Program 

(University of California) 4-11 



4.6.3 California Irrigation Management 
Information System (CIMIS) 4-11 

4.6.4 Mobil Agricultural Water Conservation 
Laboratories 4-11 

4.6.5 Other Irrigation/Drainage Management 
Services 4-12 



SECTION 5 SURVEY OF RECENT AND ON-GOING 
RESEARCH ACTIVITIES 



5.1 Areas of Investigation 5-1 

5.2 Sources of Information 5-2 

5.2.1 Periodical Literature 5-2 

5.2.2 Conference Proceedings 5-2 

5.2.3 Books, Monographs/ and Reviews 5-4 

5.2.4 Reports to Public Agencies 5-4 

5.2.5 Personal Communication 5-4 

5.2.6 Publication Lists 5-5 

5.2.7 Published Bibliographies 5-6 

5.2.8 On-Line Computer Searches 5-6 

5.3 Organization of Information 5-8 

5.4 Summary of Recent and On-Going Research 

Programs 5-8 

5.4.1 The U.S. Environmental Protection 

Agency Irrigation Return Flow Program 5-8 

5.4.2 USDA Agricultural Research Programs 5-13 

5.4.3 University of California Research 

Programs 5-14 

5.4.4 Other Research Programs in California 5-15 

5.4.5 Other Research Programs Outside 
California 5-15 



5.5 Research Proposals Related to the San Joaquin 
Valley Drainage Problem 5-15 

5.6 Grower Interviews 5-18 
SECTION 6 DISCUSSION OF MANAGEMENT ALTERNATIVES 

6.1 Potential Management Alternatives 6-1 

1. Irrigation Water Conservation 6-1 

2. Water Reuse 6-1 

3. Crop Management 6-2 

4. Soil and Subsurface Drainage System 
Management 6-2 

5. On-Farm Treatment/Storage of Drain Waters 6-2 

6. Economic/Insti tutional/Legal 6-2 

6.2 Irrigation Water Conservation 6-3 

6.2.1 On-Farm Conveyance System Efficiency 6-4 

6.2.2 Irrigation Efficiency 6-6 

6.2.3 Irrigation Scheduling 6-18 

6.2.4 Irrigation Methodology/Technology 6-26 

6.3 Water Reuse 6-35 

6.3.1 Reuse Without Blending 6-36 

6.3.2 Reuse With Blending 6-39 

6.3.3 Irrigation Water Salinity Versus 

Crop Growth Stage 6-39 

6.3.4 Subsurface Irrigation 6-40 

6.4 Crop Management 6-40 

6.4.1 Cultural Practices 6-41 

6.4.2 Crop Selection for Increased Irrigation 
Efficiency 6-42 



6.4.3 Crop Selection for Salt/Boron Tolerance 6-47 

6.5 Soil and Subsurface Drainage System Management 6-52 

6.5.1 Soil Physical Properties 6-54 

6.5.2 Soil/Irrigation Water Management 6-56 

6.5.3 Microbiological Factors 6-57 

6.5.4 Soil Amendments 6-58 

6.5.5 On-Farm Subsurface Drainage Design 6-58 

6.6 On-Farm Treatment/Storage of Drainage Waters 6-59 

6.6.1 Storage/Evaporation Ponds 6-59 

6.6.2 Reduction and/or Precipitation of 

Selenate 6-61 

6.6.3 Bio-Accumulation 6-61 

6.7 Economic/Institutional Considerations 6-63 

6.7.1 Irrigation Water Delivery 6-64 

6.7.2 Irrigation Water Pricing 6-64 

6.7.3 Drainage Effluent Pricing 6-66 

6.7.4 Removing Drainage Problem Lands 

from Production 6-67 

6.7.5 Water Quality Monitoring Systems 6-67 

6.7.6 Water Marketing 6-67 



SECTION 7 EVALUATION OF ALTERNATIVE MANAGEMENT 
PRACTICES 



7.1 Evaluation Criteria 7-1 

7.1.1 Technical Feasibility 7-1 

7.1.2 Economic Feasibility 7-3 

7.1.3 Environmental 7-4 



7.1.4 Legal/Institutional Feasibility 7-5 

7.1.5 Social 7-5 

7.2 Evaluation Approach 7-5 

7.2.1 Detailed Evaluation 7-6 

7.2.2 Feasibility Rankings 7-6 

7.2.3 Matrix Evaluation Method 7-10 

7.2.4 Overall Feasibility Determinations 7-10 

7.3 Evaluation Results 7-11 

7.3.1 Technical Evaluation 7-11 

7.3.2 Economic Evaluation 7-15 

7.3.3 Environmental Evaluation 7-18 

7.3.4 Legal/Institutional Evaluation 7-21 

7.3.5 Social Evaluation 7-21 

7.4 Evaluation Summary 7-26 

7.5 Implementation Considerations 7-26 

SECTION 8 FIELD/LABORATORY RESEARCH RECOMMENDATIONS 

8.1 General 8-1 

8.2 Research Approach 8-1 

8.3 Recommendations for Further Research 8-2 

8.3.1 Immediate Research Needs 8-2 

8.3.2 Intermediate Research Needs 8-3 

8.3.3 Extended Research Needs 8-5 

8.3.4 Summary 8-7 



SECTION 9 FINDINGS AND CONCLUSIONS 

9.1 General 9-1 

9.1.1 General Findings & Conclusions 9-1 

9.1.2 Findings and Conclusions on 

Management Practices 9-3 

9.1.3 Findings and Conclusions on Technical 
Aspects and Costs 9-4 

9.1.4 Findings and Conclusions on 
Institutional Factors 9-4 

9.1.5 Findings and Conclusions on 
Environmental and Social Factors 9-5 

9.2 Recommendations 9-5 

9.2.1 Recommended On-Farm Management 9-6 

Practices 

9.2.1 Recommended Institutional Changes 9-7 

9.2.3 Recommendations for Further Research or 

Demonstration Projects 9-8 

APPENDICES 

Appendix A - Bibliography 

Appendix B - Keyword Index 

Appendix C - Directory of Research Personnel 

Appendix D - On-Farm Agricultural Management 
Grower Survey 



LIST OF FIGURES 



Figure 2 . 1 

Figure 2.2 
Figure 3 . 1 
Figure 3 . 2 

Figure 3 . 3 

Figure 3,4 
Figure 3 . 5 
Figure 4 . 1 

Figure 6 . 1 



Figure 6 . 2 
Figure 6.3 
Figure 6.4 



Figure 6 . 5 



General Relationship of Management 
Approaches to Provide Solutions to 
Westside San Joaquin Valley Drainage 
Problems 2-4 

Vicinity Map Federal & State Water 

Service Areas San Joaquin Valley 2-6 

Summary of Existing Drainage Problem 3-2 
Areas 

The Relationship Between Soils, 
Topography, and Drainage Across 
Western Fresno County 3-7 

33 San Joaquin Valley Detailed 

Analysis Units 3-12 

Hydrologic Study Areas of California 3-16 

Typical On-Farm Water Balance 3-23 

Considerations for Selecting Cost 
Effective On-Farm Agricultural Manage- 
ment Alternatives 4-2 

Theoretical Advance and Recession 6-12 
Curves Plotted Above the Resulting 
Water Dispersion Curves for Different 
Furrow Advance Ratios 

Advance and Recession Curves for 6-14 

Border Strip Irrigation 

Effect of Reducing the Length of 6-16 

Furrow 

Illustration Using the Distribution 6-19 
Pattern in Evaluating Irrigation 
Adequacy and Adjusting the Amount of 
Water Applied to Obtain the Desired 
Adequacy 

Typical Effects of Water Distribution 6-20 
Patterns on a Crop Under Sprinkler 
Irrigation Assuming no Runoff 



Figure 6.5 Cumulative Water Use ( Evapotranspira- 
tion); Daily Water Requirement/ and 
Monthly Water Use for Cotton 

Figure 5.7 Plan and Cross-Sectional Views of 

Benched Level Basins Irrigated From an 
Unlined Channel 



6-22 
6-31 



Figure 6.8 Cross-Sectional View of Unlined 

Supply Channel From Field Road to 
Level Basin 



6-31 



Figure 5.9 Salt Movement Based on Flat Top Beds 5-43 
and Irrigation Practice 

Figure 6.10 Salinity Control with Sloping Beds 6-43 

Figure 5.11 Divisions for Qualitative Salt- 6-50 

Tolerance Ratings of Agricultural 
Crops 



LIST OF TABLES 



Table 3.1 Summary of Water Agencies, Contracted 

Water Supply, and Cost-1979 3-3 

Table 3.2 Irrigated Crop Acreage and Land Area in 

the San Joaquin Valley and California 3-11 

Table 3.3 San Joaquin Valley Groundwater Study 

Net Crop Acreage - 1980 3-13 

Table 3.4 San Joaquin Valley Hydrologic Balance 

1970 Through 1975 Average Conditions 3-15 

Table 3.5 Net Water Supply in San Joaquin and 

Tulare Lake Hydrologic Study Areas-1980 3-17 

Table 3.6 Hydrologic Balance for the San Joaquin 
and Tulare Lake Hydrologic Study Areas- 
1980 3-18 



Table 3.7 



Table 3.8 



San Joaquin Valley Detailed Analysis 

Units (DAU) and Major Water Agencies 3-20 

San Joaquin Valley Groundwater Study- 

1980 3-21 



Table 4.1 Typical Cultural Practices for Field 

Crop Production in the Study Area 4-4 

Table 4.2 Typical Cultural Practices for Truck 

Crop Production in the Study Area 4-4 

Table 4.3 Typical Cultural Practices for Alfalfa 

Hay Production in the Study Area 4-5 

Table 4.4 Summary of Irrigation Methods Commonly 

Used for Field Crop Production 4-5 

Table 4.5 Summary of Irrigation Methods Commonly 

Used for Truck Crop Production 4-6 

Table 4.6 Summary of Irrigated Crop Acreage by 
Irrigation Method in the San Joaquin 
Valley and California 4-8 

Table 5.1 Summary of Periodicals Evaluated for the 

On-Farm Agricultural Management Study 5-3 



10 



Table 5.2 Summary of On-going Research Projects 5-9 

Table 5.3 Summary of Research Proposals from the 

USDA Agricultural Research Service 5-16 

Table 5.4 Research Proposal from the Lawrence 

Berkeley Laboratory 5-17 

Table 5.5 Summary of Research Proposals from 

the Public Sector 5-19 



Table 5.6 



Table 6.1 



Table 6.2 



Table 6,3 



Table 6.4 



Table 6.5 



Table 6.6 



Table 6.7 



Table 6.8 



Table 6.9 



Summary of Private and Public Agencies 
Contacted to Assist in the On-Farm 
Agricultural Management Alternatives 
Grower Survey 5-22 

Theoretical Water Dispersion, Distri- 
bution, and Uniformity Percentage for 
Various Furrow Advance Ratios 6-13 

Factors to Consider in Selecting an 

Irrigation System (Limitations to 

Systems) 6-27 

Summary of Annual Costs for Various 

Methods of Irrigation 6-28 

Advantages and Disadvantages of 
Sprinkler Relative to Surface Irrigation 
Systems 6-33 

Guidelines for Interpretations of 

Water Quality for Irrigation 6-37 

Estimated Irrigation Efficiencies for 
Principal Crops Grown in the San Joaquin 
Valley 6-44 

Range of Costs Expected for 

Eucalyptus Firewood Plantings 6-46 

Salt Tolerance of Agricultural Crops 

Grown in the Western San Joaquin Valley 6-49 

Salt Tolerance of Selected Crops Grown 
in the San Joaquin Valley at Emergence 
and During Growth to Maturity 6-51 



11 



Table 6.10 Boron Tolerance Limits for Selected 
Agricultural Crops 



Table 6.11 



Selenium Concentrations in Plants 
Grown on Seleniferous Soils 



6-53 



6-62 



Table 7.1 Evaluation Criteria for On-Farm 
Management Alternatives 

Table 7.2 Technical Feasibility Rankings for 
On-Farm Management Alternatives 

Table 7.3 Economic Feasibility Rankings for 
On-Farm Management Alternatives 



7-2 



7-12 



7-16 



Table 7.4 Environmental Impact Rankings for 

On-Farm Management Alternatives 7-19 

Table 7.5 Legal/Institutional Feasibility Rankings 

for On-Farm Farm Management Alternatives 7-22 

Table 7.6 Social Impact Rankings for On-Farm 

Management Alternatives 7-24 



Table 7.7 Summary of Feasibility Rankings for 
On-Farm Management Alternatives 

Table 7.8 Overall Feasibility and Primary 

Limitations of On-Farm Management 
Alternatives 

Table 7.9 Example of Factors Which Affect the 

Amount of Irrigation Water Application 

Table 7.10 Example of Factors Which Affect 
Drainage Water Volume 



Table 7.11 



Example of Factors Affecting Farmer 
Decision to Implement Management 
Alternatives 



7-27 



7-29 



7-32 



7-33 



7-34 



12 



SECTION 1 
EXECUTIVE SUMMARY 



Agricultural lands on the west side of the San Joaquin Valley are 
becoming increasingly impacted by rising saline shallow groundwater 
as a result of irrigation with water primarily from federal and state 
water projects. This problem is not the result of the irrigation 
water source but is caused by a combination of: 1) geologic and soil 
conditions which restrict downward movement of water below the crop 
root zone; 2) native soil salinity; and 3) inefficient irrigation 
water management. The problem is most pressing toward the foot of 
the alluvial fans originating from the Coast Range Mountains on the 
western edge of the San Joaquin Valley where flat topography and very 
slow permeability soils do not allow adequate natural drainage. 

A valley-wide master drain was originally planned to dispose of 
agricultural waste waters into the Delta-Suisun Bay area which is 
directly connected to the San Francisco Bay. However/ the master 
drain was not constructed because of the projected high construction 
cost and environmental concerns over inorganic and organic chemical 
constituents in the drainage waters. In lieu of a valley-wide 
master drain, the U.S. Bureau of Reclamation (USBR) began 
construction of a concrete-lined drainage canal (San Luis Drain) to 
remove drainage waters from the San Luis Unit federal service area. 
Also constructed to temporarily hold these waters was Kesterson 
Reservoir, a series of ponds 12 miles north of Los Banos. 

Following disclosure of bird mortalities in the Kesterson Reservoir 
caused by selenium from the introduced drainage waters and concern 
for public health, the Department of Interior in a March, 1985 
agreement with Westlands Water District called for the cessation of 
all drainage flows into the reservoir by June 30, 1986. 

The San Joaquin Valley Drainage Program was initiated with 
representatives from the USBR, the U.S. Fish and Wildlife Service, 
the U.S. Geological Survey, and California Departments of Fish and 
Game and Water Resources to investigate possible alternatives to 
provide a solution to the San Joaquin Valley agricultural drainage 
problem. One of the drainage management options is to reduce 
drainage flows through on-farm management practices. On-farm 
agricultural management is an important element of the overall 
solution to drainage problems because the cost of treatment and/or 
disposal can be lowered by reduction of drainage flow volumes. 
Boyle Engineering Corporation contracted with the USBR to identify 
and evaluate various on-farm management practices that could be used 
to reduce drainage flows or to improve drainage water quality on the 
west side of the San Joaquin Valley. 

Although the hydrologic balance for the San Joaquin Valley is 
documented, there has been very little critical evaluation of the 
quantity of irrigation water percolating to shallow groundwater 

1- 1 



aquifers or draining and seeping into surface water courses. This 
has made it difficult to estimate the total contribution of various 
agricultural management practices to the drainage problem. 
Nevertheless, specific practices can be evaluated with respect to 
their potential for reducing drainage flows or improving drainage 
water quality. It is the objective of this study to identify on-farm 
management practices that could be used to reduce subsurface 
drainage flows and/or improve drainage water quality. The 
management practices are evaluated with regard to their technical 
and economic feasibility. Institutional, environmental, and social 
constraints are also considered where applicable. 

Information on management practices was obtained through public and 
university libraries, on-line computer searches, and conversations 
with individuals conducting research on management practices that 
could be employed in effecting a solution to the drainage problem. 
Background information on the study area was obtained primarily from 
the California Department of Water Resources. Other information on 
the environmental setting, historical background, and existing 
agricultural environment was obtained from various sources. 
Referenced documents are cited in the bibliography and cross- 
referenced through a keyword index. A directory of technical 
experts conducting research that may have application to the 
solution of the drainage problem is also included. A grower survey 
was also conducted to determine existing on-farm management 
practices under different cropping systems and drainage problems and 
to ascertain constraints to improving irrigation efficiency. 

Potential management practices were grouped into four major 
categories: 1) water conservation practices that could improve 
irrigation efficiency and thus reduce percolation losses; 2) reusing 
drainage waters for irrigation; 3) crop and soil management 
practices to reduce drainage flows or to cope with increasing soil 
salinity; and 4) on-farm storage/treatment of drainage waters. The 
most prominent category is water conservation practices which center 
on improving on-farm irrigation efficiencies through use of more 
advanced irrigation systems, better water control and measurement, 
improved irrigation scheduling and management, and improved on-farm 
conveyance systems. The reuse of drainage water centers on 
subsurface drainage water recovery systems and tailwater recycling. 
Crop management practices largely center on cultural practices to 
use water more efficiently and to adapt to higher soil salinity 
levels that may result from improved irrigation efficiency. Soil 
management includes practices using soil physical, chemical, and 
biological properties to reduce subsurface drainage flows either 
directly or in conjunction with other management practices. Since 
even the best management practices will still result in percolation 
requiring subsurface drainage, on-farm storage and treatment of 
these drainage waters is also considered. The technical, economic, 
and legal considerations relative to on-farm evaporation ponds are 
briefly discussed. Other treatment considerations include the bio- 
accumulation of toxic elements from soils and the reduction and 
precipitation of soluble selenium in the soil and drainage systems. 



1- 2 



On-fariti management alternatives are evaluated on technical/ 
economic, environmental, institutional, and social merits. Most of 
the management alternatives are technically feasible, but 
sophisticated management practices beyond the capabilities of many 
farming operations may be required. Economic feasibility is highly 
variable. Many management practices are relatively inexpensive and 
require little investment in materials and equipment. These 
include irrigation scheduling, existing flood/furrow irrigation 
system improvements, system maintenance, and the control and 
measurement of applied water. Several public and private service 
organizations can assist in these practices. More expensive 
methods such as advanced automated irrigation systems are costly 
while their benefits are hard to quantify. Environmental impacts 
must be weighed as part of the alternative evaluation process. 
Serious problems can result from growing vegetation to lower the 
water table or to accumulate contaminants into vegetative biomass. 
Trace elements such as selenium could be introduced into the food 
chain . 

Current rules and regulations provide little incentive to encourage 
technically and economically feasible management practices. This 
is especially evident in areas not having immediate drainage 
problems but contributing to downslope or downstream drainage 
problems. Current water pricing policies are largely reflected in 
federal and state water contracts and do not generally encourage 
drainage flow reduction or water conservation. Changes in water 
pricing and water rights principles will require changes in long- 
entrenched concepts which may prove to be politically difficult to 
achieve . 

The term "research" as used in this report refers to basic and applied 
research as well as field scale evaluations and demonstrations. 
Research priority to address immediate, intermediate, and extended 
research needs is suggested. Immediate and intermediate research 
could produce alternatives that offer rapid improvement of 
subsurface drainage conditions, but additional data (primarily 
economic) and grower education are needed. Immediate research 
needs could: 1) reduce pre-irrigat ion ; 2) improve technologies for 
measuring plant moisture stress; 3) improve water measurement and 
control; 4) improve existing flood/furrow irrigation systems; and 5) 
improve grower education. Intermediate research would be directed 
toward evaluating alternatives that appear to offer a feasible 
technical solution to the drainage problem. Additional technical 
and economic research and grower education are required to provide 
data needed to make implementation decisions. Intermediate 
research needs should be directed at: 1) surge irrigation and 
cablegation; 2) level-basin technology; 3) linear move irrigation 
system; 4) traveling-trickle irrigation system; 5) subsurface 
trickle (drip) irrigation; 6) drainage water reuse for irrigation; 
7) drainage water recovery systems; and 8) variable row spacing. 
Extended research should focus on those practices having technical 
and economic questions that need further examination. Extended 

1- 3 



research should be direct to: 1) surface-drained level basin; 2) 
subsurface drainage system design and management; 3) on-farm 
storage/evaporation ponds; 4) transplanting; 5) precipitation and 
absorption of selenium; 6) agrof orestry ; 7) selection of crops for 
salt/boron tolerance; 8) volumetric water application for 
flood/furrow irrigation systems; 9) subirrigation ; and 10) bio- 
accumulation . 

Growers need technical and cost information to make sound decisions 
on management practices. Present research has generally not 
addressed this need and methods of information dissemination to 
educate growers have not been effective. Research efforts should be 
coordinated by a federal/state agency or task force having practical 
knowledge of farm operations and the complex technical issues 
involved. The research work should be contracted to agencies and/or 
private firms with the demonstrated capability of performing timely 
research . 

Effective management practices and grower education can 
significantly ameliorate the drainage problems on the west side of 
the San Joaquin Valley. New areas of research will develop from on- 
going efforts. On-going evaluation; integration/ and demonstration 
programs will provide public education and assistance to growers. 

Implementation involves complex issues. The technical/ economic/ 
institutional/ environmental/ and social aspects vary between 
different management alternatives. Usually costs govern on-farm 
management decisions exclusive of rules and regulations established 
by federal/ state/ and local agencies. Growers control internal 
factors and manage their operations to maximize returns in 
accordance with their particular circumstances. Thus/ a grower 
will apply a systems approach to select management alternatives 
consistent with his operational ability and financial conditions. 

Growers in drainage problem areas need to improve subsurface 
drainage conditions to maintain productive farms/ but upslope 
farmers who often contribute to downslope drainage do not feel 
obligated to operate differently since they are not directly 
impacted. These upslope growers will probably not participate in 
correcting subsurface drainage problems until they are required by 
regulation or are provided sufficient economic incentive. 

Regulatory action may provide incentives or disincentives to 
participate in corrective actions. Increasing the cost of 
irrigation water would encourage water conservation. However, 
because of the current low water price, significant increases would 
be needed to effectively reduce water use. Growers who have 
implemented water conservation measures and those not contributing 
to the drainage problem could be harmed by ill conceived regulations. 
Regulatory changes to provide incentives should be carefully 
designed to avoid undue penalties. 



1- 4 



SECTION 2 
INTRODUCTION 



2.1 STATEMENT OF THE PROBLEM 

With the irrigation of lands on the Westside of the San Joaquin Valley 
from state and federal water project facilities, water is being 
increasingly added to the shallow groundwater as a result of 
inefficient irrigation and seepage from conveyance facilities. The 
geology of the western San Joaquin Valley contributes to a dilemma 
for agricultural water users. Vertical seepage of shallow 
groundwater is restricted by heavy clay lenses. The shallow 
groundwaters therefore are forced to move downslope to attain 
hydrologic equilibrium. The net result is a gradually rising 
shallow groundwater table. Productive agricultural lands on the 
west side of the San Joaquin Valley are impacted by the shallow 
perched water table. 

Agricultural drainage problems have existed in the San Joaquin 
Valley since irrigation began in the 1870's. Extensive 
agricultural acreages were abandoned by 1900 because of salt and 
alkaline problems. Through the construction of deep drains and 
heavy leaching some lands were reclaimed; however, salt accumulation 
and drainage continued to be a problem. The development and 
installation of subsurface drains around 1950 increased the 
discharge of poor-quality saline water. This has resulted in the 
progressive degradation of subsurface drainage water quality making 
reuse more difficult and adversely impacting the water quality of the 
San Joaquin River. When the federal and state governments began 
studies to plan and construct major water supply projects to serve 
the San Joaquin Valley, planning was also initiated to provide 
subsurface drainage water disposal facilities because of the 
historic drainage problems that had occurred. 

The United States Congress under the San Luis Unit Authorization Act 
(PL 86-488) authorized construction of the San Luis Unit in 1960, 
which included allocations for facilities required to dispose 
subsurface drainage flows from lands within the unit. The U.S. 
Department of Interior, Bureau of Reclamation started construction 
of the San Luis Drain in 1968. About 85 miles of the drain and the 
first stage of Kesterson Reservoir were constructed, but the project 
was stopped in 1975 as a result of funding problems and environmental 
concern related to drainage discharge impacts to the Delta. 

The Interagency Drainage Program (IDP) evaluated several different 
drainage water disposal alternatives during the period between 1975 
and 1978. The IDP report concluded that construction of a master 
drain for export/disposal of valley saline drainage waters to the 
western Delta was the most economical and environmentally acceptable 
solution. As a result of the IDP report, the USER initiated the 
required procedures needed to obtain a permit from the State Water 

2- 1 



Resources Control Board (State Board) to discharge drainage water 
flows to the Bay-Delta Estuary. The USBR initiated the San Luis Unit 
Special Study in 1981 to: 1) supplement the San Luis Unit 
Environmental Impact Statement filed in 1972 regarding the impact of 
a drainage discharge to the Delta Bay Estuary; 2) analyze alternative 
drainage management plans; and 3) develop information required by 
the State Board to establish drainage effluent criteria. 

The technical studies required by the State Board were largely 
complete when the Kesterson wildlife problems were discovered. 
Based on the findings at Kesterson, additional studies were needed to 
thoroughly evaluate the drainage water contaminant problems and 
reformulate alternatives for providing a drainage management 
program for lands in the San Joaquin Valley. Because of these needs, 
the San Joaquin Valley Drainage Program was established. 

The discovery of high selenium levels in western San Joaquin Valley 
subsurface drainage water changed both the magnitude and the focus of 
the drainage water disposal problem. Historically, the drainage 
water disposal problem focused on the management of salts for the 
protection of agricultural land and the impact of nitrogen or boron 
on receiving waters. The problem as now understood emphasizes the 
management of salinity and pollutants as well as drainage water 
contaminants, including trace elements such as arsenic, boron, 
chromium, molybdenum, nickel, and selenium. 




The San Joaquin River is extensively developed and regulated. Large 
volumes of agricultural subsurface drainage water flows and runoff 
are discharged directly or indirectly into the San Joaquin River 
system, resulting in degradation of San Joaquin River water quality, 
especially during low flow conditions (summer and fall). The 
degradation of San Joaquin River water quality is having significant 
adverse effects on resident and anadromous fish and its use for 
downstream agricultural and municipal/ industrial uses. 

The USBR estimates indicate that approximately 77,000 acres of the 
land in the San Luis Unit-Delta Mendota Canal Service area (CVP) are 
now being drained and that an additional 174,000 acres currently need 
subsurface drainage. The total area requiring subsurface drainage 
will increase to about 380,000 acres by the year 2020 and 
approximately 495,000 acres by the year 2095 (USBR, Information 



2- 2 



Bulletin 3, 1984). Areas requiring subsurface drainage in the San 
Joaquin Valley are projected to be in excess of 1,000,000 acres by the 
year 2085 (IDP, 1979) . 

Subsurface drainage water beneath agricultural lands constitutes a 
significant threat to agricultural productivity, wildlife 
resources, and the quality of life for residents of the San Joaquin 
Valley. Continued discharges of subsurface drainage waters will 
cause further degradation of soil/water and wildlife resources. 
Yet agriculture, which forms the economic backbone of the San Joaquin 
Valley and the State of California, must be protected. Therein lie 
the elements of this complex problem. How can the quality of life be 
protected and wildlife habitat enhanced while providing 
treatment/disposal of these subsurface agricultural drainage flows? 
Any solution to these problems must include the removal of 
saline/toxic contaminants which flow from beneath agricultural 
lands in the San Joaquin Valley or agricultural production can not be 
sustained . 

The reduction of subsurface drainage flows from agricultural lands 
or the improved quality of those flows is a significant factor in 
determining treatment/disposal methodology and cost. The study 
reported herein addresses the potential implementation of on-farm 
agricultural management alternatives and attempts to identify the 
feasibility of improving drainage water quality or reducing flows. 
Even if significant technically feasible management alternatives 
are available, their implementation will likely require painful and 
time consuming economic, social, legal, and political decisions. 

2.2 STUDY OBJECTIVES 

The solution to the complex problem of properly dealing with 
subsurface drainage flows from agricultural lands in the western San 
Joaquin Valley requires an integrated program to collect, treat, and 
dispose of these waters. The relationship of the on-farm management 
consideration to other elements of the solution is shown in Figure 
2.1. As previously stated, the quantity and quality of subsurface 
drainage waters have a significant impact on treatment/disposal 
approaches and cost. Thus, the implementation of alternative 
agricultural management techniques is an important element in the 
overall solution to the subsurface drainage management problem. 
The costs for implementing on-farm management alternatives to 
provide solutions to the drainage problems should be allocated to 
source lands. The drainage problem source lands include not only 
existing drainage problem lands but also adjacent lands which may be 
contributing to the problem as a result of inefficient farm 
irrigation practices. 

A variety of alternatives has been studied to evaluate their 
potential implementation as a means of dealing with agricultural 
subsurface drainage flows. These former studies have not 
thoroughly addressed the potential for reducing the quantity or 

2- 3 



GENERAL RELATIONSHIP OF MANAGEMENT 

APPROACHES TO PROVIDE SOLUTIONS TO 

WESTSIDE SAN JOAQUIN VALLEY 

DRAINAGE PROBLEMS 



OTHER SURFACE 
WATER SUPPLY 



TAILWATER 



GROUNDWATER 
SUPPLY 



ON-FARM 

AGRICULTURAL 

MANAGEMENT 

PRACTICES 



CVP/SWP 

CONTRACT WATER 

SUPPLY 



PERCHED WATER 



WATER AGENCY 
SUPPLY 



SUBSURFACE 
DRAINAGE WATER 



ON-FARM 
TREATMENT /DISPOSAL 
ALTERNATIVES 



ON-FARM 

EVAPORATION 

BASIN 



DRAINAGE FLOW 
QUANTITY/QUALITY 



SAN JOAQUIN -_ 
RIVER r» 



VALLEY 
DRAINAGE 
DISPOSAL SYSTEM 



DISPOSAL OF 
BRINE/TOXICANTS 



OFF-FARM 

TREATMENT DISPOSAL 

ALTERNATIVES 



DEEP WELL 
INJECTION 



I 



OFF-FARM 

EVAPORATION 

BASIN 



DESALINIZATION/ 
DETOXIFICATION 



-{ 



DISPOSAL OF 
BRINE/TOXICANTS 



BcK.0e Enalnaatlncy CorfDorattcDn 



FIGURE 2 



J 



2-4 



improving the quality of agricultural subsurface drainage by 
modifying current crop management/production practices. The 
objective of this task order is to evaluate what can be done with on- 
farm agricultural management practices to reduce the salinity and 
contaminant problems, particularly selenium, occurring under 
current practices and to identify institutional constraints and 
incentives which must be considered in such a program. 

The objectives of the On-Farm Agricultural Management Study are 
summarized as follows: 

o Review existing literature to identify relevant potential on- 
farm management alternatives. 

o Identify and evaluate past, on-going, and future agricultural 
research related to on-farm agricultural management alterna- 
tives . 

o Develop a consolidated data base of relevant literature. 

o Identify feasible on-farm management alternatives by evaluating 
technical, economic, environmental, and institutional factors. 

o Evaluate the cost, benefits, and efficiency of reducing 
subsurface drainage flows or improving subsurface drainage 
water quality for feasible management alternatives. 

o Identify research programs needed to provide data necessary to 
perform feasibility analyses for management alternatives that 
cannot be fully evaluated because of insufficient existing data. 

2.3 STUDY APPROACH AND SCOPE OF WORK 

High concentrations of selenium in Federal Service area lands appear 
to be restricted primarily to the Panoche, Little Panoche, and Cantua 
Creek fans. The areas of high selenium levels recently discovered 
in the State Water Project (SWP) service area include Wheeler Ridge 
and Lost Hills Water Districts. This area within the SWP service 
area encompasses some 220,000 acres of alluvial soils formed from 
materials weathered from the sedimentary rocks found in the Coastal 
Mountain Range. 

The study examines both the federal Delta Mendota Canal and San Luis 
Unit service areas and the State Water Project service area as shown 
in Figure 2.2. Initial efforts were directed toward the Panoche Fan 
area which encompasses the 42,000 acre area contributing to 
discharges into the San Luis Drain. The study also assesses 
conditions in the remaining study area where drainage systems exist 
or will eventually be required. The study focuses on identifying 
and evaluating alternatives that have the potential to impact 
drainage water quantity/quality at the farm drainage outlet. 
Alternative treatment/disposal facilities, such as evaporation 

2- 5 



VICINITY MAP 

FEDERAL & STATE WATER SERVICE AREAS 

SAN JOAQUIN VALLEY 



^SAN-tOlS res' 
\ 

PANOCHE FAN 




CVP SAN LUIS 
SERVICE AREA 



Soc/te Enaineertncj CarporsOon 



FIGURE 2.2 



J 



2-6 



basins, that may be employed after the water is discharged from in- 
field drains are not considered in the study. 

To efficiently accomplish the project goal, the required work was 
separated into the following six major tasks: 

o Review existing published/unpublished literature and research 
data including on-going research. 

o Conduct field interviews with selected growers in the study 
area . 

o Identify existing agricultural management practices. 

o Identify feasible agricultural drainage management alterna- 
tives . 

o Determine field/laboratory research program requirements. 

o Prepare final report. 

A discussion of the scope of work performed under each task follows. 

2.3.1 Review Existing Published/Unpublished Literature and 
Research Data Including On-Going Research 

Discussions were held with the San Joaquin Valley Drainage Program 
Study Team, local study area water districts, federal and university 
researchers, and other responsible agencies and parties to assemble 
data on suggested agricultural management methods to deal with the 
current drainage problem. Published and unpublished reports and 
results from on-going studies were obtained from agencies such as the 
USBR, U.S. Department of Agriculture Agricultural Research Service, 
USGS, State of California Department of Water Resources, University 
of California Agricultural Extension, Fresno County Agricultural 
Commissioner, Westlands Water District, Environmental Defense Fund, 
Land Preservation Association, Natural Resources Defense Council, 
Delta Mendota Water Users Association, etc. These reports were 
evaluated to ascertain the historic and present agricultural 
conditions and management practices in the Delta Mendota Canal and 
San Luis Unit service areas. 

Based on the literature review, the study attempts to identify the 
salinity and contaminant elements of the drainage water and how they 
may be affected by proposed on-farm agricultural management 
alternatives. Knowledgeable researchers and professionals in 
federal and state agencies and universities were contacted and 
interviewed to determine and evaluate past, present, and anticipated 
research programs and to discuss potential agricultural management 
alternatives related to the study area. The review of these data 
facilitated the identification of the potential agricultural 
management alternatives. The Interagency Study Team screened 

2- 7 



alternatives submitted to them and selected ten for further review by 
Boyle. The work performed in this task resulted in the development 
of a list of potential agricultural management alternatives which 
was used as the basis for further evaluations in later study work 
tasks. The data collected were organized for reference and easy 
retrieval using computer facilities. 

2.3.2 Conduct Field Interviews 

Irr igator s . in the study area have firsthand experience in managing 
subsurface drainage problems and are a source for identifying 
additional alternatives. It was judged that adequate data were 
probably not available to evaluate all identified potential 
alternatives. The field interview approach provided an opportunity 
to obtain on-site data needed to address issues and provide data not 
adequately summarized in the available literature. The field 
interviews also afforded growers in the study area an opportunity to 
provide input into the evaluation of the potential management 
alternatives . 

A format for the field interviews was developed to address the 
pertinent issues based on the range of potential alternatives 
initially identified by the literature review. The Interagency 
Study Team and other selected agencies were given an opportunity to 
review and comment on the questionnaire prior to conducting the 
interviews. Irrigators in the Delta Mendota Canal and San Luis Unit 
service areas and SWP service area were asked to respond to the 
questionnaire to gain additional information about the viability of 
alternatives and to identify additional alternatives. Information 
on current agricultural cropping and management practices was also 
gathered . 

2.3.3 Identify Existing Agricultural Management Practices 

The data developed from the literature review and interviews were 
consolidated to identify general crop management practices and 
costs. Existing agricultural management conditions in the western 
San Joaquin Valley area were characterized to be used as the basis of 
comparison for evaluating the costs and benefits which could be 
derived from implementing the on-farm agricultural management 
alternatives . 

2.3.4 Identify Feasible On-Farm Agricultural Drainage Management 
Alternatives 

On the basis of developed data and field reviews, the potential 
alternatives were studied further to identify those considered 
feasible. The feasibility of each alternative was evaluated on the 
basis of technical, economic, environmental, social, and 
institutional factors. The criteria used for the evaluation were 
developed by Boyle. Once feasible alternatives were identified, 
the requirement for additional field/laboratory research studies 
was determined. 



2- 8 



2.3.5 Determine Field/laboratory Research Program Requirements 

Future field/laboratory studies are required to properly evaluate 
the potentially feasible alternatives to adequately verify 
hypotheses and fill gaps in existing data. A program to accomplish 
the required field/laboratory research studies is identified along 
with the recommended approach. The proposed program was reviewed 
with the appropriate researchers in order to provide an opportunity 
to coordinate the recommended program with on-going research and 
reduce any duplication of effort. 

2.3.6 Prepare Final Report 

Boyle provided monthly written progress reports to summarize work 
and findings and to identify work activities for the next month. The 
results of the study are presented in this report. 



2- 9 



SECTION 3 
CHARACTERISTICS OF THE PROJECT AREA 



3.1 LOCATION OF STUDY AREA 

The study area is located on the westside of the San Joaquin Valley of 
California (see Figure 3.1). The study area is separated into two 
drainage basins. The San Joaquin basin in the north drains into the 
Sacramento-San Joaquin Delta and into San Francisco Bay through the 
San Joaquin River; the valley's only natural outlet. The Tulare 
basin in the south is separated from the San Joaquin basin by a low 
alluvial ridge. Excess flows that may occur during years of above- 
normal precipitation collect in the Tulare Lake basin because this 
system does not have a low level outlet to the sea. 

The study is focused toward areas in the San Joaquin Valley that 
currently have or are expected to have subsurface drainage or salt 
management problems. Most of these areas are within the federal and 
state water service areas. A summary of the water agencies located 
in the study area and the amount of their contracted water supply and 
cost is given in Table 3.1. The conclusions and recommendations 
that result from this study may apply to other irrigated lands 
outside the study area where agricultural subsurface drainage waters 
are causing degradation of groundwater or downstream water supplies. 

The federal service area extends from about Kettleman City north to 
about Tracy and includes portions of Fresno, Kings, Merced, San 
Joaquin, and Stanislaus Counties. The area totals approximately 

1.2 million acres divided about equally between the San Luis Unit and 
Delta-Mendota Canal service areas. Irrigation water deliveries are 
provided to the service areas by CVP facilities which include the San 
Luis and Delta-Mendota Canals. A total of 36 water districts 
deliver irrigation water to individual farms. 

Areas impacted by subsurface drainage problems are shown on Figure 
3.1. About 251,000 acres are currently affected by drainage 
problems in the federal service area. These lands are impacted by 
inadequate drainage or because discharged subsurface drainage water 
is adversely affecting valley lands and the San Joaquin River. 
Subsurface drainage water from approximately 77,000 acres (about 31% 
of the affected area) north of Mendota is discharged by water 
districts into the San Joaquin River. Subsurface drainage from 
about 8,000 acres within the 42,000 where the project collector drain 
system is located west of Mendota in Westlands Water District has 
been discharged directly into Kesterson Reservoir through the San 
Luis Drain. All drainage discharges into Kesterson were terminated 
by June 30, 1986 because of the waterfowl problems associated with 
drainage water storage in the reservoir and in accordance with an 
April 3, 1985 agreement between Westlands and the Department of the 
Interior. About 174,000 acres of agricultural lands presently need 



3- 1 




10 20 



EXPUVNATION 

I J B*cr»m«nto.B«n Joaquin DatU 

0-D' 0«plh \o Orountf W«l*r 
e'-10' Dapth lo Oround Walar 



Source: USBR, February 1985 



SUMMARY OF EXISTING DRAINAGE PROBLEM AREAS 



BOL0B EnejtfmMxrtTo CcsrrxxiatMjn 



FIGURE 3.1 



3-2 



TABLE 3.1 
SUMMARY OF WATER AGENCIES, 
CONTRACTED WATER SUPPLY, AND COST-19791/ 



Agency 


County 


Maximum 
Detailed!' Entitle- 
Analysis ment t. 
Unit Water Source (ac-ft)- 


Water 
Cost 
($/ac-ft) 


Water Districts 












Westlands 


Fresno 


244 


Mendota Pool, 50,000 
San Luis Canal 1,100,000 


16.15 


San Luis 


Fresno 


— 


San Luis Canal 
Delta Mendota Canal 


52,000 
73,080 




Berrenda Mesa 


Kern 


259 


Calif .Aqueduct 




56.00 


Cawelo 


Kern 


256 


Calif .Aqueduct 


45,000 


59.00 


Henry Miller 


Kern 


254 


Kern River, 
Calif .Aqueduct 


41,800 


16.20 


Kern Delta 


Kern 


254 


Kern River, 
Calif .Aqueduct 


30,000 


11.97 


Lost Hills 


Kern 


259 


Calif .Aqueduct 




42.00 


West Kern Co. 


Kern 


260 


Calif .Aqueduct 


25,000 




Devil's Den 


Kings 


245 


Calif .Aqueduct 




44.15 


Dudley Ridge 


Kings 


246 


Calif .Aqueduct 




37.19 


Broadview 


Fresno 


216 


Delta-Mendota Canal 




17.00 


Mercy Springs 


Fresno 


216 


Delta-Mendota Canal 




3.90 


Oro Loma 


Fresno 


216 


Delta-Mendota Canal 




5.50 


Panoche 


Fresno 


216 


Delta-Mendota Canal 
San Luis Canal 




8.30 


Widren 


Fresno 


216 


Delta-Mendota Canal 




NA 


Centinella 


Merced 


216 


Delta-Mendota Canal 




3.75 


Eagle Field 


Merced 


216 


Delta-Mendota Canal 




4.90 


Lag una 


Merced 


216 


Mendota Pool 




NA 



3- 3 



Table 3.1, continued 



Agency 



County 



2/ 
Detailed-' 


Maximum 


Entitle- Water 


Analysis 


ment , , Cost 
(ac-ftK ($/ac-ft) 


Unit Water Source 



Water Districts, continued 



Stevinson 



Merced 216 



Mustang 


Merced 


216 


Quinto 


Merced 


216 


Ftomero 


Merced 


216 


San Luis 


Merced 


216 


Del Puerto 


Stanislaus 


216 


El Solyo 


Stanislaus 


216 


Foothill 


Stanislaus 


216 


Hospital 


Stanislaus 


216 


Kern Canyon 


Stanislaus 


216 


Oak Flat 


Stanislaus 


216 


Orestimba 


Stanislaus 


216 


Patterson 


Stanislaus 


216 



Salado Stanislaus 216 

Sunflower Stanislaus 216 
Water Storage Districts 

Belridge Kern 259 

Buena Vista Kern 255 



San Joaquin River, 3.20 
Merced River 

Delta-Mendota Canal 3.65 

Delta-Mendota Canal 3.75 

Delta-Mendota Canal 3.75 

Delta-Mendota Canal 20.80 

Delta-Mendota Canal 3.75 

San Joaquin River 14.00 

Delta-Mendota Canal 3.75 

Delta-Mendota Canal 4.00 

Delta-Mendota Canal 4.00 

Delta-Mendota Canal 36.60 

Delta-Mendota Canal 3.70 

San Joaquin River, 26.00 
Delta Mendota Canal 

Delta-Mendota Canal 3.75 

Delta-Mendota Canal 4.00 

Calif .Aqueduct 35.00 

Calif .Aqueduct 25,000 6.58 

Friant/Kern 

(surplus) 



3-4 



Table 3.1, continued 



Agency 



,2/ 



Detailed- 
Analysis 
County Unit Water Source 



Water Storage Districts, continued 



Rosedale- 
Rio Bravo 



Semitropic 



Tulare Lake 
Basin 



Kern 



Kern 



Wheeler Ridge- Kern 
Maricopa 



Kings 



254 



255 



261 



241 



Cross Valley 
Canal, Calif. 
Aqueduct 



Maximum 

Entitle- Water 
ment 3 / Cost 
(ac-ft)~ ($/ac-ft) 



35,000 



Calif .Aqueduct 183,000 
Kern River, 
Friant-Kern Canal 

Calif .Aqueduct 302,900 



Calif .Aqueduct, 110,000 
Kings River 



14.07 



40.00 



49.25 



m. 



Irrigation Districts 
Empire Westside Kings 



241 



W.Stanislaus Stanislaus 216 



Central Calif. Fresno, 216 
Merced , 
Stanislaus 



Kings River 
Calif .Aqueduct 



3,000 



San Joaquin River, 
Central Valley Project 

Central Valley Project 



7.70 



16.60 



5.50 



1/ U.S. Department of Interior, U.S. Department of Agriculture and 
~ U.S. Environmental Protection Agency, 1979. 

2/ For definition of detailed analysis units see Section 3.3.1, 
"" Page 3-10. 

3/ Contractual arrangements for SWP water through the Kern County 
Water Agency (Total maximum entitlement = 1,153,400 acre-feet) . 



3- 5 



drainage but do not have access to drainage water disposal 
facilities. Agricultural land ultimately requiring subsurface 
drainage is expected to increase to approximately 380/000 acres by 
the year 2020 and 495,000 acres by 2095, or about 41 percent of the 
land in the federal service area. 

The state service area extends from about Kettleman City south to the 
Tehachapi Mountains and includes portions of Kern and Kings 
Counties. The area totals approximately 1.4 million acres. 
Irrigation water deliveries are provided to 15 water districts 
through the California Aqueduct. Subsurface drainage water from 
approximately 87,000 acres in the state service area is currently 
discharged into unlined evaporation ponds in the Tulare Lake basin. 
Drainage water from an additional 5,000 acres is discharged directly 
into the south fork of the Kings River. About 135,000 acres of 
agricultural lands currently requiring drainage do not have access 
to subsurface drainage water disposal facilities. Based on data 
provided by the California Department of Water Resources, 
agricultural land requiring subsurface drainage in the state service 
area is expected to ultimately total approximately 720,000 acres, or 
about 50 percent of the service area. 

3.2 ENVIRONMENTAL SETTING 

3.2.1 Physiographic Setting 

The study area constitutes a portion of the San Joaquin Valley of 
California bounded on the west by the Coast Range, the north by the 
Sacramento-San Joaquin Delta, the northeast by the San Joaquin 
River, the east by approximately the valley trough, and the south by 
the Tehachapi Mountains. The natural drainage of the north half of 
the study area is northeasterly to the San Joaquin River which 
eventually joins the Sacramento River before exiting into San 
Francisco Bay via Suisun Bay and the Carquinez Straits. The 
southern half of the study area does not have a low elevation natural 
drainage outlet to the ocean. It partially or totally includes 
Tulare, Buena Vista, and Kern Lakes which are normally dry except in 
years of above-normal precipitation when runoff waters draining from 
the Sierra Nevada Mountains to the east are allowed to run into the 
lake basins. 

3.2.2 Geology and Hydrology 

The geologic structure of the study area (Figure 3.2) generally 
consists of alluvial sedimentary layers derived from the Coast Range 
to the west which gradually slope eastward to the valley trough. The 
fine-grained nature of the marine and non-marine sedimentary rocks 
of the Coast Range is reflected in the fine textured alluvial soils 
derived from these formations. Old buried stream channels of 
coarser materials are laced through shallow alluvial deposited fans 
and interfans formed by streams from the Coastal Range. These sand 
and gravel stringers allow more rapid downslope movement of 

3- 6 



ca 

< 



* 

>- 



a. 
< 
ee 

C9 



CO "- 



CO UJ 



I- Vi 

UJ c/) 

ca o 

- s 

=: < 




L 



Boua Ei nj t M MaticjCXii u ui a t kj n 



FIGURE 3.2 



3-7 



drainage waters than would normally be expected from the generally 
fine-textured soils. 

The groundwater aquifer is largely contained in two water bearing 
strata composed of sands, gravels, and discontinuous clay lenses 
separated by a thick (about 60 feet) continuous clay layer at 
variable depth. This clay layer, referred to as the Corcoran clay, 
is highly impermeable to water movement. This is evidenced by the 
fact that the piezometric head of the deeper, confined aquifer is 
above the Corcoran clay. The depth of the shallower, unconfined 
aquifer decreases in the direction of the valley trough. The 
direction of the hydrologic gradient, however, is not precisely 
known. With increasing irrigation from imported water supplies 
into the study area, evidence is accumulating that the gradient is 
primarily in an easterly or northeasterly direction. Because of the 
stratified nature of the alluvial deposits, vertical movement of 
percolation water from irrigation is restricted resulting in the 
buildup of a shallow perched water table which may or may not be 
continuous with the unconfined aquifer above the Corcoran clay. 
Horizontal movement of this shallow water body, however , is much less 
restricted because of the presence of coarser textured strata and 
buried stream channels. 

The water of the shallower aquifer is moderately saline, (e.g. less 
than 750 ppm) reflecting the marine origin of the sediments and 
historic irrigation with groundwater of relatively high salinity 
from below the Corcoran clay. Where the shallow water table is close 
to the soil surface, evapotranspiration removes water leaving 
residual concentrations of salts that can restrict vegetative 
growth. Rainfall in the study area, which ranges from about 10 
inches in the north to about 4 inches in the south (University of 
California Special Publication 3285, 1983) , is insufficient to leach 
these soils of their accumulated salts. 

3.2.3 Climate 

The climate of the western San Joaquin Valley is arid. It is 
characterized by two distinct seasons. The hot dry summer extends 
from about April to October. Average rainfall during the summer is 
less than .25 inches. Most of the annual rainfall occurs in the cool 
winter season usually during January, February, and March. Annual 
average rainfall increases from south to north and west to east. The 
Tracy area at the north end of the study area averages about 10 inches 
while south of Bakersfield the average annual rainfall is about 4 
inches. Annual rainfall is not adequate to support economic yields 
of dryland crops. 

Summertime temperatures are high with maximum temperatures ranging 
from about 100 to 110 degrees Farenheit during much of the period. 
Daytime high temperature usually does not vary markedly from south to 
north. However, average daily temperature is typically lower in the 
north because of the nighttime cooling influence of the delta area. 

3- 8 



These cooler temperatures restrict the suitability of crops like 
cotton in the north part of the federal service area. Wintertime 
average daily temperature is lower in the north because of the 
persistent valley fog. This fog tends to burn off in the late 
mornings further south, which usually allows a significant increase 
in daytime temperature. The small difference between winter night 
and daytime temperatures in the approximate north half of the federal 
service area makes this area better suited to deciduous tree and vine 
crops. Freezing temperatures often occur at night during 
wintertime in the federal and state service areas and early morning 
frosts are common. Prolonged freezing temperatures, snow, strong 
winds, or thunderstorms are rare in the study area. 

3.2.4 Soils and Vegetation 

Soils of the project area consist of alluvial and lacustrine deposits 
derived from the sedimentary rocks of the coastal mountains and the 
granitic rocks of the Sierra Nevada mountains. Soils west of the 
valley trough (basin) are generally derived from the softly 
consolidated calcareous sandstones and shales of the coastal 
mountains. Soils in the valley basins and eastward are derived 
largely from the granitic Sierra Nevada Mountains. Typically soils 
in the federal and state water service areas have surface textures 
ranging from moderately fine to fine. Coarser textured soils are 
often found along the eastern edge of the area near the foothills of 
the coastal mountains. Because of the alluvial nature of study area 
soils, the profile exhibits significant stratification with many 
soils having restricted internal drainage. Soils are typically 
moderately to strongly calcareous with adverse salinity and 
alkalinity problems often associated with lands in valley trough. 

Native vegetation consisted largely of annual grasses and broadleaf 
plants. Near the lower edge of the alluvial fans, in the basin rim 
areas where salt and alkali concentrations are present, the 
vegetation consisted largely of salt/alkali tolerant plants. The 
valley basin area supported a dense growth of tules and tule grasses 
with some willow and cottonwood trees. Remaining native vegetation 
in the project area is confined to limited areas that are not used for 
agriculture . 

3.3 AGRICULTURAL SETTING 

Agriculture is California's largest industry and has historically 
provided the basis for the state's rapid growth and diversification. 
The heaviest concentration of agricultural activity is in the San 
Joaquin Valley with three counties, Fresno, Tulare, and Kern ranked 
first, second, and third, respectively among the United States' 
leading counties in agricultural revenue in 1984. Merced and San 
Joaquin counties are also in the top ten. Because of limited 
rainfall in the valley, crop production depends on irrigation from 
surface and groundwater supplies. 



3- 9 



3.3.1 Irrigated Acreage 

Total irrigated agricultural acreage for California was estimated at 
about 10,088,500 acres in 1985, up from approximately 10,024,000 
acres in 1980, and 8,759,000 acres in 1975 (Irrigation Journal, 
January, 1986). The California Department of Water Resources 
estimated irrigated acreage at about 5,526,000 acres in the San 
Joaquin Valley in 1980, more than one-half the total irrigated 
acreage in California. The 1972 and 1980 estimated crop acreages by 
principal crops grown in the San Joaquin Valley are summarized in 
Table 3.2 (California DWR, 1983) . In 1980, 90 percent of the state's 
cotton acreage was planted in the San Joaquin Valley. 

More detailed 1980 crop acreage estimates were obtained by the San 
Joaquin District of the DWR for their San Joaquin Valley Groundwater 
Study. The DWR divided the San Joaquin Valley into 33 detailed 
analysis units (DAU) corresponding to areas of similar water supply 
and water use characteristics (Figure 3.3). Crop acreages were 
estimated for each DAU. These estimates are obtained from periodic 
land use surveys conducted by the DWR approximately every 7 years for 
prime agricultural land and are augmented by data from the California 
Crop and Livestock Reporting Service and annual reports from County 
Agricultural Commissioners' offices. 

Estimated crop acreages for each DAU located in the study area in 1980 
are summarized in Table 3.3. In DAU 216, which includes the Delta- 
Mendota Canal service area, nearly 28 percent of the crop acreage was 
planted to cotton while about 16, 10, 9, and 7 percent of this acreage 
was planted to miscellaneous field crops, alfalfa, deciduous fruits 
and nuts, and grain. In DAU 244, which includes the Westlands Water 
District, about 51 percent of the total acreage was planted to cotton 
and approximately 22 percent to grain. For those DAU ' s in the State 
Water Project (SWP) service areas in the San Joaquin Valley, about 50 
percent of all irrigated acreage is planted to cotton while grain and 
alfalfa are planted to approximately 18 and 10 percent of the SWP 
acreage. Based on the available data, the approximate southern half 
of the federal service area and the entire state service area are 
largely planted to annual field crops. 

3.4 WATER CONDITIONS 

3.4.1 Hydrologic Balance 

The hydrologic balance (water balance) considers the transfer of 
water into and out of a defined earth volume. This volume, or 
hydrologic unit, is normally defined as a portion of the earth's 
surface whose upper boundary is the land surface and whose lower 
boundary is some geologically-defined barrier to water movement. 
The area of a unit may be characterized by a common physical feature 
such as a drainage outlet (hydrologic basin) or by some water 
boundary (edge of a river or lake) . The area may also be a political 
unit such as a country, region, state, county, water district, or 



3- 10 



TABLE 3.2 
IRRIGATED CROP ACREAGE AND LAND AREA IN 
THE SAN JOAQUIN VALLEY AND CALIFORNIA 
(1,000 acres)!/ 



Crop 



2/ 2/ 

San Joaquin Tulare Lake California 
1972 1980 1972 1980 1972 1980 



423 


319 


1,234 


986 


605 


500 


1,050 


1,485 


5 


13 


349 


545 


715 


1,239 


883 


1,545 


130 


67 


1,334 


1,041 


380 


285 


1,450 


1,318 



Field Crops 

Alfalfa 286 181 

Grain 99 275 

Rice 31 41 

Cotton 119 197 

Irrigated pasture 422 301 

Other 416 484 
Fruit & Nut Crops 

Orchard 318 

Grapes 148 

Vegetable Crops 209 

TOTAL CROP ACRES 2,048 

DOUBLE CROP 19 

TOTAL 2,029 2,062 3,016 3,312 8,779 9,490 



341 


371 


445 


1,279 


1,352 


176 


330 


363 


548 


683 


146 


122 


153 


919 


969 


2,142 


3,081 


3,384 


9,046 


9,824 


80 


65 


72 


267 


434 



1/ California Department of Water Resources, 1983. 

2/ Hydrologic Study Areas as defined by the Department of 
~ Water Resources. 



3-11 



/- 




+ 



33 SAN JOAQUIN VALLEY 
DETAILED ANALYSIS UNITS 



Bc3utB Encjtntitiit mj CotxJorBOon 



FIGURE 3.3 



3-12 





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3-13 



farm. The criteria for determining such a unit are based on the 
information needed and the ease of obtaining that information. The 
fluxes of water into and out of a unit through its many pathways are 
measured or calculated in order to determine that unit's net water 
balance . 

The State of California calculates a water balance by determining the 
difference between the water supply and net water use. The water 
supply is determined from the sum of surface water imports, 
groundwater pumpage, and reclaimed water. The net water use is: 1) 
that water lost by evaporation and transpiration of applied water, 
precipitation, and surface water supplies and 2) that water lost to 
saline bodies of water. 

A detailed hydrologic balance network for California is described by 
the California Department of Water Resources (1983). The average 
hydrologic balance for the San Joaquin Valley for the period 1970 
through 1975 is summarized on Table 3.4. Based on these data, the 
San Joaquin Valley at that time was operating under a water deficit 
system . 




California's approach to determining net water supply does not 
consider losses of water by percolation to saline shallow water 
tables (see Figure 27, DWR Bulletin 160-83) . On a state-wide basis, 
percolation losses were estimated at about 7.4 million acre-feet in 
1980. For the San Joaquin and Tulare Lake HSA's they were estimated 
at about 1.28 and 3.56 million acre-feet. There are little data to 
determine quantities of deep percolating water that contribute to 
agricultural return flows to rivers, reservoirs, and canals either 
as point discharges or as non-point seepage. Surface return flows 
were estimated at about 8.1 million acre-feet for the state with 
approximately 623,000 and 82,000 acre-feet in the San Joaquin and 
Tulare Lake HSA's respectively in 1980 (California DWR, 1983). 

3.4.2 San Joaquin Valley Groundwater Studies 

In response to state legislation passed in 1978 (Nejedly, 1978), 357 
groundwater basins in the State of California were identified by the 
DWR in order to facilitate better groundwater management (California 
DWR, 1980). The San Joaquin Valley is divided into fifteen primary 
basins based on political as well as geologic and hydrologic 
considerations. To facilitate management decisions, the DWR 

3- 14 



TABLE 3.4 
SAN JOAQUIN VALLEY HYDROLOGIC BALANCE 
1970 THROUGH 1975 AVERAGE CONDITION^' 



DWR's Base Balance 

Supply/Disposal Acre-Feet (thousands) 

Items of Supply 

Precipitation 4,914 

Local stream inflow 7,923 

Import through California Aqueduct 1,098 

Import through Delta-Mendota Canal 2,094 

Decrease in storage of San Luis 

Reservoir and O'Neill Forebay 156 

Subsidence 211 

Subsurface inflow 

Items of Disposal 



15,396 



Evapotranspirat ion of precipitation 

Cropped land 2,846 

Non-cropped land 1,612 

Evapotranspiration of applied water 

Agriculture 9,437 

Wildlife preserves 95 

Municipal and industr ial (consumptive use) 180 

Evaporation and evapotranspiration of riparian 

vegetation from rivers, major canals, and 

San Luis Reservoir 230 

Evaporation from distribution canals 178 

Local stream outflow (San Joaquin River) 2,319 

Export through California Aqueduct 279 

Losses to moisture deficient soils 58 

Subsurface outflow 12 

17,246 

Change in groundwater storage - 850 

1/ California DWR Bulletin 214 (1982) 

3-15 



HYDROLOGIC STUDY AREAS 

OF 

CALIFORNIA 



NC - MOJIH COASI 
S F - SAN fJANCrSCO iAY 
C C . CENIBAl. COAST 
LOS ANGELES 
SANIA ANA 
SAN DIEGO 
SACRAMENTO 
SAN JOAOUIN 
TULA«E LAKE 
NO«TH LAHONTAN 
SOUTH LAHONTAN 
COIOJADO «IVH 



I A 
S A 
S 
s > 

S J 
T L 
N I 
S L 
C ( 




Source: DWR, December 1982 



BoLjli^ Encjlnestinci Corporsaan ■ 



3-16 



FIGURE 3.4 



TABLE 3 . 5 
NET WATER SUPPLY IN SAN JOAQUIN AND TULARE LAKE 
HYDROLOGIC STUDY AREAS - 198ol 
(1,000 acres) 



Source 



San Joaquin 
San Joaquin Tulare Lake Valley 



Surface Supply 
Local surface water 
Central Valley Project 
Other Federal (non-CVP) 
State Water Project 
Waste water reclamation 
Total 

Groundwater Supply 

2/ 
Prime Supply 

Overdraft 

Total 

Total Net Supply 



3,055 

1,838 

55 

8 

21 

4,977 

972 

391 
1,363 
6,340 



2,199 

2,736 

243 

1,536 

67 

6,781 

551 

856 

1,407 

8,188 



5,254 

4,574 

298 

1,544 

88 

11,758 

1,523 

1,247 

2,770 

14,528 



_!/ Source: California Department of Water Resources Bulletin 
160-83 (1983). 

2_/ Includes long-term average addition to groundwater basin 
from precipitation, recharge from rivers and streams, and 
artificial recharge. 



3-17 



TABLE 3.6 
HYDROLOGIC BALANCE FOR THE SAN JOAQUIN AND , , 
TULARE LAKE HYDROLOGIC STUDY AREAS - 1980 - 
{1,000 acre-feet) 



San Joaquin Tulare San Joaquin 
Basin Lake Valley 

2/ 
NET WATER SUPPLY 6,340 8,188 14,528 

NET WATER USE 

Agricultural Use 

ETAW 4,474 7,326 11,800 

Return flow & spillage to 
downstream areas in HSA 

Return flow to Delta 

Flows to salt sinks 

Riparian & distribution 
system ET 

Other Losses 177 74 251 

Subtotal 5,892 7,781 13,673 

Other Use 89 48 137 

Urban Use 249 236 485 

Conveyance Losses 

(CVP) 111 93 204 

(SWP) 30 30 

TOTAL ALL USES 6,340 8,188 14,528 



1/ Source: California DWR Bulletin 180-83 (1983). 
2/ From Table 3.5. 



561 




561 


382 




382 




276 


276 


298 


105 


403 



3-18 



performed a more detailed study of groundwater conditions in 1979 
(California DWR, 1982). The DAU ' s identified in this study (see 
Figure 3.2) are within the major water agencies in the San Joaquin 
Valley (see Table 3.7). For example, the water agencies in the 
Delta-Mendota Canal service area are DAU 216 while Westlands Water 
District is DAU 244. The area of this groundwater study is not 
directly comparable to the state HSA's since it excludes the 
Consumnes and Mokelumne River drainages and the mountains 
surrounding the valley floor. 

The major g.oal of the San Joaquin Valley groundwater study was the 
development of a hydrolog ic-economic model to be used to evaluate 
groundwater management policies (California DWR, 1982) . Included in 
this model was the Surface Water Allocation Model (SWAM) . This 
model was designed to compute a surface-water budget for the San 
Joaquin Valley that would take into account major surface-water 
sources, demands, and losses. The San Joaquin Valley surface-water 
system is represented in the model as a system of interconnecting 
channels and junctions. Input data include quantities of water 
flowing into the valley from streams and canals and from estimated 
rainfall in each DAU. Crop water use is calculated from estimated 
crop acreages and crop evapotranspiration requirements in each DAU. 
Estimates of crop acreages are obtained from county agricultural 
commissioners, the California Crop and Livestock Reporting Service, 
and reports of various water agencies. Crop evapotranspiration 
requirements are obtained from California DWR Bulletin 113-3 (1975) . 
Total applied water is estimated by dividing the evapotranspiration 
of applied water (ETAW) by an estimate of irrigation efficiency 
(California DWR, 1982). ETAW and estimated applied water for each 
DAU in 1980 are summarized in Table 3.8. The difference between ETAW 
and applied water is considered as excess water that is lost from the 
DAU by deep percolation or surface runoff. Estimates are not made to 
determine the quantity of water lost as a result of deep percolation 
that emerges as return flows to rivers, canals, or reservoirs. The 
hydrologic balance for the study area was averaged for the years 1970 
to 1975 for input into the DWR groundwater models. 

3.4.3 On-Farm Water Balance 

On-farm management technologies aimed at reducing seepage losses 
from on-farm conveyance systems and deep percolation losses from 
applied water must be viewed in the context of the field scale water 
balance. The water balance in the soil can be defined as follows: 

Re + I = ET + DP + RO + AS 

where Re is effective rainfall, I is irrigation, ET is annual 
evapotranspiration, DP is deep percolation, RO is runoff, and AS is 
the change in moisture content of the root zone. 

Effective rainfall is defined by the DWR as that portion of the total 
rainfall used by the crop. All rainfall during the growing season is 



3-19 



TABLE 3.7 
SAN JOAQUIN VALLEY DETAILED ANALYSIS UNITS (DAU) AND 
MAJOR WATER AGENCIES i' 



Detai led 
Analysis 

Unit Name 



Major Water Agencies 



Pr imary 
Water Source 



216 Delta-Mendota 



Central California ID 
West Stanislaus ID 
Patterson WD 



CVP 

Delta Mendota 



241 Tulare Lake 



Tulare Lake Basin WSD 
Corcoran ID 



SWP 



244 Westlands 



Westlands WD 



CVP 

San Luis 



245 Kettleman 
Plain 



Pleasant Valley WD 
Devil's Den WD 



SWP 



246 South Tulare 
Lake 



Dudley Ridge WD 
Hacienda WD 



SWP 



254 Kern Delta 



Kern Delta WD 
Rosedale-Rio Bravo WSD 



SWP 



255 Semitropic 



Semitropic WSD 
Buena Vista WSD 



SWP 



259 Antelope 
Plain 



Belridge WSD 
Berrenda Mesa WSD 
Lost Hills WD 



SWP 



260 Buena Vista 
Valley 



West Kern WD 



SWP 



261 Arvin-Wheeler 
Ridge West 



Wheeler Ridge- 
Maricopa WSD 



SWP 



ID - Irrigation District 

WD - Water District 

WSD- Water Storage District 

1/ Adapted from California DWR Bulletin 214 (1982) . 



3-20 



TABLE 3.8 , , 

SAN JOAQUIN VALLEY GROUNDWATER STUDY - 1980-' 
(1,000 acre-feet) 



Detailed 




Appl 


ied Water 




Evaporation of Appli 
Agricult. Urban 


Led 


Water 


Analysis 


Agi 


ricult. 


Urban 


Total 


Total 


Unit 


Acre-feet 


Acre-feet 


Acre-feet 


Acre-feet 


Acre- feet 


Acre-feet 


216 


1 


,578.2 


12.3 


1,590.5 


937.7 


4.2 




941.9 


241 




704.7 


3.3 


708.0 


492.3 


1.2 




493.5 


244 


1 


,582.0 


5.9 


1,587.9 


1,102.6 


2.2 


1 


,104.8 


245 




121.8 


4.9 


126.7 


85.4 


1.7 




87.1 


246 




110.4 


0.1 


110.5 


76.9 







76.9 


254 




801.6 


92.1 


893.7 


515.0 


32.5 




547.5 


255 




641.7 


1.1 


642.8 


414.3 


0.4 




414.7 


259 




439.0 


0.2 


439.2 


303.3 


0.1 




303.4 


260 




4.6 


6.4 


11.0 


3.2 


2.2 




5.4 


261 




252.3 


0.2 


252.5 


175.5 


0.1 




175.6 


TOTAL 


6 


,236.3 


126.5 


6,362.8 


4,106.2 


44.6 


4 


,150.8 



1/ Adapted from California DWR Bulletin 214 (1982). 



3-21 



r?fnf!?/°H^V^^^''^'''^' °""^"5 th^ non-growing season, only that 
?hTYctaf "■' ""' ^-1"°-- DWr',1980) for the pe°.od 184, to"97r 

the net a„oun't of water passilg^Srough'the" op rol?zrne'?R?,"°"Th: 

- o r-^^^ei - p-^^^3s--f;o/r.'-/f-r;at-r'a^^^r^'^^^ 



llot^LtT7aVe"\t7 r''°]'''°" '°"^= contribute to a shallow 
across the f,.i^V„' } "P (vertical) and horizontal seepages 

ITrl'lT T. '''^'^^ '"' "^"P Pe-ou"?!on°lossls.''"h'e=/entr?l":„'! 
farm water balance is illustrated in Figure 3.5. '"^ general on- 

3-'1.4 Salt Balance 

s'oi^-p^rf !e"-£K /-">'r"-° -- 

^.'?o-ed-tVe%=? orsr-ble-L^i:'iSw-SCS^ 

Lli„!?y ruYd eg^ui"lfbra't^e''gen\\anr t"\\\t'"o'f "^T'^ ?°" 
water. However, agricultural cropt'U^um'e "at°e'r to%r'ow:'"h?s" 

3- 22 



'^ 



TYPICAL 

ON-FARM WATER BALANCE 




Bcjuie Ertot-mart-KjCuiuuimacjn 



FIGURE 3.5 



3-23 



water is lost by evapotranspirat ion from the plant and adjacent soil 
surfaces. Since the water lost is essentially pure, the salt 
component remains in the soil. Therefore, waters percolating below 
the root zone will always have a higher salt concentration than that 
of the irrigation water. 

This only becomes a critical problem when the salinity of the soil 
solution exceeds the crop salt tolerance. In order to maintain soil 
salinity below this level, a net flux of salts through the root zone 
needs to be maintained. To obtain this salt balance, the net 
quantity of salts passing through the root zone must equal that which 
is introduced from the salts of the irrigation water supply. When 
this equality is maintained, a salt balance has been achieved in the 
crop root zone. 

The water passing through the root zone will be more saline than the 
irrigation water by a factor equivalent to the ratio of the amount of 
applied water to the amount of water passing through the root zone. 
This can be simply stated in the following equation: 

Vi = Sd 
Vd Si 

where V and S are the volume and salinity of water and i and d are the 
applied water and water passing through the root zone (deep 
percolation). From this equation it can be seen that as the ratio 
Vi/Vd increases, the salinity of the drainage water should increase 
with respect to irrigation water such that the total quantity of 
salts introduced by irrigation is balanced by the quantity of salts 
drained . 

This is a relatively simple explanation of the salt balance in the 
soil profile. Not considered was the presence of mineral salts 
which are subject to precipitation and dissolution. This may have a 
drastic effect on drainage water salinity, especially if native 
salts are dissolved into the soil solution. In this case the 
salinity of percolated water may be much higher than predicted by the 
salt balance equation. Thus, a small percentage reduction in 
applied water will result in a major percentage reduction in salts 
passing through the root zone. Likewise, excess water application 
will result in a high flux of salts below the root zone and into 
drainage systems (Rhoades, 1983). 

3.4.5 Drainage Water Quality 

Early concern about drainage water quality centered on salinity, and 
to some extent boron, where drainage water was to be reused for 
irrigation. As recently as 1960, an investigation of surface, 
ground, and drainage water quality in the lower San Joaquin Valley 
(DWR, 1960) reported conductance, TDS , chloride, sulfate, sodium, 
and boron. These constituents were discussed primarily with 
reference to irrigation water suitability. A more recent DWR report 

3- 24 



referred to total salinity (conductance) in its study of water 
quality in the lower San Joaquin River (DWR Bull. 143-5, 1969). 

In 1959, the DWR initiated the Drainage Monitoring Program. 
Beginning in 1969, the USBR assisted in collecting samples from the 
north end of the valley. The program was continued on a limited 
basis under the auspices of the Interagency Drainage Program (IDP) 
from 1975 to 1979. In 1980, the program resumed as a separate 
activity under the DWR San Joaquin Valley Drainage Monitoring 
Program without the assistance of the USBR because of funding 
limitations. Through 1963, subsurface drainage waters were 
analyzed for total salinity and major mineral composition. Prior to 
1974, there was only sporadic analysis of trace elements. In 
response to increasing environmental concern over trace elements, 
arsenic, cadmium, chromium, copper, iron, lead, and zinc were 
identified by the Central Valley Water Quality Control Board as 
potentially hazardous and were analyzed (DWR-DMP-1975) . The only 
reported trace element which was detected in the southern area was 
arsenic in 1980 (DWR-DMP-1975). The USBR initiated a monthly 
sampling program in the Federal Service Area in 1982 with some 
samples analyzed in 1981. In 1984, the DWR-DMP summarized selenium 
analyses from samples collected during 1981 to 1983 (DWR-DMP-1984 ) . 

3.5 HISTORICAL PERSPECTIVE 

3.5.1 Early Development of Irrigation Facilities in the 
San Joaquin Valley 

The history of agriculture in the San Joaquin Valley has been one of 
expansion of irrigation into areas once used for dryland wheat 
farming or grazing. From the 1870's into the 1920's, many farms were 
created from larger land holdings. These farms typically consisted 
of 20-acre parcels sold with associated water rights with water 
usually supplied by a local water company from stream diversions. 
Prior to 1900, artesian wells supplied additional water with pumping 
of groundwater becoming increasingly necessary after about 1900. 

The need for improved water supply facilities eventually led to the 
formation of publicly held irrigation districts. After 1915 
legislation, the districts could be financed more easily by state- 
backed bond sales. By 1922, three million acres in California were 
served by irrigation districts. Irrigation districts provided 92 
percent of the irrigation water used in the San Joaquin Valley by 1930 
(Kahrl, 1979). 

3.5.2 Development of State and Federal Water Projects 

Increasing pressure for state involvement in a region-wide water 
project for the San Joaquin Valley followed the drought years of 1928 
to 1935 when groundwater overdraft and pumping costs increased 
sharply. In 1920, Colonel Robert B. Marshall proposed a state-wide 
water plan that was soon widely endorsed by agricultural interests. 

3- 25 



The state proceeded with comprehensive studies to evaluate the plan 
but found that little could be done because region-wide water 
transfers were restricted by a tangled, complex, legal system of 
riparian water rights laws. This hurdle was partially overcome by a 
constitutional amendment passed in 1928 limiting owners of riparian 
rights to reasonable use of water (Kahrl, 1979). 

In 1933, the state legislature approved a $170 million state bond to 
finance the Central Valley Project, an outgrowth of Marshall's state 
water plan. President Franklin D. Roosevelt authorized the funding 
of the project in 1935 with construction to be carried out by the 
Bureau of Reclamation. In August, 1951, water began flowing in the 
Delta-Mendota and Friant-Kern Canals. Provisions were not included 
to address subsurface drainage problems and subsequently most 
subsurface drainage was directly discharged into the San Joaquin 
River. This discharge raised the river's salinity much above 
historical levels. (DWR Bull. 87, 1960). 

The California State Water Resources Board was created in 1945. 
This agency was directed to inventory California's water resources 
and develop plans for a state-financed water project. The result 
was a series of publications inventorying the water resources of 
California (SWRCB, 1951 and 1955) and the publication of the 
California Water Plan (DWR, 1957). The need to install a master 
drain in the San Joaquin Valley was recognized in the California 
Water Plan. This facility was needed to alleviate expected drainage 
problems from additional irrigation supplies to the southern San 
Joaquin Valley and to avoid further degradation of downstream water 
quality from additional agricultural return flows. 

In 1959, the State Water Resources Development Bond Act (Burns- 
Porter Act) was passed by the legislature, setting in motion the 
construction of the State Water Project. Because of increasing 
concerns with drainage water quality and quantity, a provision for a 
master drain was included in the act. Water deliveries began in 1962 
with 1.3 million acre-feet allocated to the San Joaquin Valley, 
including 788,000 acre-feet to the Kern County Water Agency. 

In 1960, Congress enacted the San Luis Unit Authorization Act (PL 86- 
488) , which provided for the construction of the San Luis Unit of the 
federal CVP. The Westlands Water District was to be the primary 
contractor for this water. Included in the authorization was a 
provision to drain agricultural waste waters from the service area to 
the Delta. Since environmental concerns slowed further CVP and SWP 
development, the National Water Commission in 1973 recommended that 
the USER redirect its efforts more toward water management functions 
to insure that water supplies would be efficiently used. (Kahrl, 
1979). Construction of the drain to the Delta was stopped in 1975 
due to environmental concerns. 



3- 26 



3.5.3 Developinent of Drainage Facilities in the San Joaquin 
Valley 

An early experiment in which tile drains were installed east of the 
Fresno Slough was reported by Fortier and Cone (1909). Another 
early tile drain system was tested in a vineyard on the Kearney Ranch 
(Weir, 1916). From 1915 on, irrigation districts increasingly 
assumed responsibility for the construction of tile drains and 
drainage ditches east of the valley trough. With the advent of deep 
well pumping in the 1920's, a drop in the shallow groundwater table 
resulted in less need for drainage east of the valley trough 
(Kellers, 1984) . 

With irrigation, the focus of San Joaquin Valley drainage problem was 
directed to the valley trough. The Central Valley Project 
contributed much to this problem with diversions of high quality San 
Joaquin River water into the Friant-Kern Canal at Friant Dam and with 
import of poorer quality water from the Delta-Mendota Canal. 
Further, control of tributary streams, which did not result from CVP 
facilities, reduced summer month river flows. Since provisions 
were not made for system-wide agricultural waste water drainage, 
these waters were directed either back to the distribution system or 
directly to the San Joaquin River, severely affecting water quality 
downstream from Mendota (DWR, Bull. 89, 1960). To determine the 
scope of this problem, an investigation was initiated in 1955 by the 
Department of Water Resources (DWR Bull. 89, 1960). A Joint 
Legislative Committee on Water Problems met in 1957 and called for a 
comprehensive master drainage works system (Calif. Leg., 1957). As 
a result of this meeting, the San Joaquin Valley Drainage 
Investigation was initiated under the direction of the DWR. The 
result of this investigation was a DWR bulletin recommending the 
construction of a jointly financed federal-state San Joaquin Valley 
Master Drain from near Bakersfield to the Antioch Bridge in the 
Delta. In addition, the San Joaquin Valley Drainage Monitoring 
Program was initiated in 1959 by the DWR in cooperation with the 
University of California to monitor the quality of agricultural 
drainage waters. 

The Burns-Porter Act (1959) authorized financing and construction of 
the State Water Project, including provisions for facilities to 
remove drainage waters from the San Joaquin Valley (DWR Bull. 127-74, 
1974) . In the same year, the San Luis Unit Authorization Act (Public 
Law 86-488) was enacted. The act required that the USBR either 
participate with the state to provide a master drainage outlet or 
construct the San Luis Interceptor Drain to the Delta designed to 
meet the drainage requirements of the San Luis Unit (IDP, 1979). In 
1961, the DWR notified the USBR that the State could not assure 
construction of a master drain. Since the San Luis Unit 
Authorization Act required drainage to be provided, the Secretary of 
the Interior announced in 1963 the construction of the San Luis 
Interceptor Drain to begin in 1966 with service beginning in the San 
Luis Unit in 1968. In 1963, the DWR resumed discussions with the USBR 



3- 27 



regarding the construction of a joint federal-state master drain 
facility. In 1967, the DWR sent a proposal to the USER for the 
construction of a 280-niile concrete lined master drain which would 
include the San Luis Interceptor Drain. The first stage from near 
Kettleman City to the Delta would be completed by July 1, 1978. 
However, after three years of joint federal-state planning, the DWR 
notified the Bureau (March 10, 1967) that it could not assure 
repayment of the state's reimbursable costs and requested the Bureau 
to proceed with construction of the San Luis Interceptor Drain as 
presented in the San Luis Unit Authorization Act. 

3.5.4 The San Joaquin Valley Drainage Advisory Group 

At the request of the DWR, the San Joaquin Valley Drainage Advisory 
Group was created in 1967 to review waste water disposal 
requirements, recommend a project to meet these needs, and develop a 
plan for repayment of the state's reimbursable costs. In the final 
report (SJVDAG, 1969) , the Group recommended the staged construction 
of a single joint-use federal-state drain from near Gustine in Merced 
County (current terminus of the San Luis Drain) to an outlet at the 
Delta near the Antioch Bridge. Recommendations made by the Advisory 
Group were never enacted because the federal and state governments 
could not reach agreement. 

3.5.5 The San Joaquin Valley Interagency Drainage Program 

After a hiatus of several years during which time an 82-mile segment 
of the San Luis Drain was constructed, the San Joaquin Valley 
Interagency Drainage Program (IDP) was formed in 1975 to re-evaluate 
the alternatives for drainage management. Participating agencies 
were the USER, DWR, and the California SWRCB. Several alternative 
proposals for agricultural drainage water disposal were presented 
with the IDP recommending a valley-wide master drain discharging to 
Suisun Bay near Chipps Island by 1981. Based on the available data, 
this was considered the most economical and environmentally sound 
alternative. Included in the drainage system was a series of 
wetland marshes managed both as wildlife habitats and reservoirs to 
regulate drain water discharge to the Delta-Suisun Bay. The IDP 
recommendation addressed the water quality problems evident at the 
time: salinity and nitrate-nitrogen. The final report (IDP, 1979) 
concluded that the movement of the SJV master drain outlet to a more 
westerly location because of lower project costs would not cause 
widespread salinity increases in the Western Delta-Suisun Bay area 
and would not cause significant impact on algae growth. However, 
nitrate removal was considered as potentially necessary to ensure 
algae control given projected drainage water quality in the year 
2000. 

The primary concern identified in the EIR included in the final IDP 
report was the potential impact of subsurface drainage water 
constituents on aquatic life. Concern was raised primarily for 
boron, chromium, iron, lead, mercury, and certain pesticides as 

3- 28 



being at potontially toxic levels for aquatic life. More intensive 
drainage monitoring was recommended but selenium was not included. 



3- 29 



SECTION 4 
EXISTING ON-FARM MANAGEMENT PRACTICES 



4.1 GENERAL 

Existing on-farm management practices reflect the soil; water 
supply, and climatic factors that dictate the economics in the 
development of the prevailing cropping pattern. The consideration 
of general farm management practices is an important element of the 
study because the existing practices are based on maximizing returns 
from crop production. Thus/ the implementation of alternative on- 
farm management practices will likely result in a modification of 
existing practices which may reduce profits. Increased costs may 
result from a combination of cultural/ labor/ operational/ 
maintenance/ and capital/interest factors. Conversely/ some 
alternatives with high capital cost may allow the reduction of 
certain crop production costs. For example/ the cost of subsurface 
drip irrigation systems is high/ but these high costs may be 
somewhat offset by reduced labor/ irrigation water/ cultivation and 
fertilizer costs. The implementation of alternatives must be based 
on an economic comparison of existing crop production practices and 
costs . 

A general schematic which represents the approach to the evaluation 
and implementation of on-farm agricultural management alternatives 
is shown on Figure 4.1. Farm managers must consider the range of 
potential on-farm management alternatives as they relate to the 
characteristics of their particular operation and management 
capability. The alternative must be shown cost effective before 
implementation will proceed. 

4.2 CULTURAL PRACTICES 

Cultural practices refer to the annual variable cost inputs such as 
ground preparation/ cultivation/ labor/ fertilizer/ pesticides/ 
etc. Crop cultural practices vary throughout the study area as a 
result of different levels of management capability and machinery 
availability. The crop rotation on a particular farm may also 
influence certain cultural practices. For example/ growers who 
rotate with sugar beets often grow cotton on 30-inch rows to reduce 
labor and equipment associated costs. Crop cultural practices for a 
particular crop usually do not vary appreciably between growers. 
What typically varies is the equipment used to perform a certain 
cultural operation or time during the crop growth cycle at which the 
operation is performed. These elements relate to the management and 
equipment capabilities previously mentioned. The bulk of the study 
area is planted to annual crops. These crops require annual soil 
preparation and planting. Several crops planted on significant 
acreage in the study area also require tillage during the growing 
season. At the end of the crop growth cycle after harvest/ plant 

4- 1 



a 



CONSIDERATIONS FOR SELECTING COST EFFECTIVE 
ON-FARM AGRICULTURAL MANAGEMENT ALTERNATIVES 



Existing Crop 

Management 

Practices 






Determine Range 

of Suitable On-Farm 

Management Alternatives 



I 



Evaluate 

Cultural 

Requirements 




Evaluate 

Machinery 

Requirements 



Evaluate 

Irrigation /Drainage 

Requirements 



Evaluate 
Labor Requirement 



Implement Cost Effective 

On-Farm Management 

Alternatives 



BoLjte ErxytriBBrtncj Ca nJ t j raaon 



FIGURE 4.1 



4-2 



residues are incorporated into the soil and preparation is begun for 
the next crop. Permanent crops which are planted on a smaller 
percentage of the study area require minimum tillage practices 
during the growing season. Cultural practices applied to these 
crops consist mostly of fertility, pest control, and crop 
management . 

Crops grown in the study area can be divided into four general 
categories: 1) permanent crops; 2) field crops; 3) truck crops; and 
4) forage crops. Cultural practices are generally similar for the 
crops in each specific category but differ between the categories. 

The major permanent crops grown in the area consist of grapes, 
almonds, stone fruits, pistachios, and other deciduous fruits and 
nuts. Establishment of a permanent crop requires high labor and 
machinery costs the first year and usually until the crop reaches 
maturity. These types of crops are not suited to drainage problem 
areas because they will not withstand shallow groundwater conditions 
and usually yield poorly on fine textured soils. However, they are 
grown on farms upslope from drainage problem areas. Irrigation 
systems used for these crops are typically solid set sprinkler, drip, 
or flood with short water runs. Most identified on-farm management 
alternatives apply to these crops with the exception of certain 
automated irrigation systems such as linear move and center pivot 
systems. 

Field crop production requires many different cultural operations. 
Table 4.1 summarizes practices commonly used to produce the major 
field crops grown in the area. Truck crops include vegetables such 
as melons, potatoes, onions, and garlic. These crops require 
cultural practices that are often labor and machine intensive. 
Table 4.2 summarizes practices generally used for truck crop 
production in the study area. Forage crops in the area consist 
primarily of alfalfa grown for hay production. Alfalfa hay is 
usually included in a three year rotation with cotton or other annual 
crops. Table 4.3 summarizes practices required for alfalfa 
establishment. 

4.3 IRRIGATION MANAGEMENT PRACTICES 

Irrigation management practices vary appreciably between different 
irrigation systems, crops, and growers in the project area. The 
types of irrigation systems commonly used for crops typically grown 
in the study area are summarized in Tables 4.4 and 4.5. The major 
factor in attaining acceptable irrigation efficiency is related to 
the proper design and operation of a particular irrigation system and 
the timing and duration of irrigation. Irrigation scheduling is 
particularly important in crop irrigation. Methods for scheduling 
crop irrigations vary from sophisticated computer irrigation 
scheduling models to the calendar approach. 



4- 3 



TABLE 4.1 
TYPICAL CULTURAL PRACTICES FOR FIELD CROP PRODUCTION 

IN THE STUDY AREA 





Small 






Saf- 


Sugar 


Field 


Grain 




Alfalfa 


Practice 


Grain 


Rice 


Cotton 


f lower 


Beets 


Corn 


Sorghum 


Beans Seed 


1/ 




















Chisel 


X 


X 


X 


X 


X 


X 


X 


X 


X 


Disc 


X 


X 


X 


X 


X 


X 


X 


X 


X 


Harrow 


X 




X 


X 




X 


X 


X 


X 


Float 2/ 






X 






X 




X 




Plane 2/ 




X 






X 








X 


List 








X 


X 










Shape Beds 










X 










Fur row 2/ 






X 






X 


X 


X 


X 


Cultivate 






X 


X 


X 


X 


X3/ 


X 


X 


Build Levees 


X 
















Level Pits 




X 

















Dependent on subsoil conditions. 

system used. 



2^/ Dependent of type of irrigation 
T/ Dependent on type of plantings. 



TABLE 4.2 
TYPICAL CULTURAL PRACTICES FOR 
TRUCK CROP PRODUCTION IN THE STUDY AREA 







Onion 










and 






Practice 


Tomatoes 


Garlic 


Potatoes 


Cantaloupes 


1/ 










Chisel 


X 


X 


X 


X 


Disc 


X 


X 


X 


X 


Harrow 


X 


X 


X 


X 


Plane2/ 


X 


X 


X 


X 


Float2/ 








X 


List 


X 


X 


X 


X 


Shape Bed 


X 


X 


X 


X 


Furrow2/ 






X 




Cultivate 


X 


X 


X 


X 



\_/ Dependent on subsoil conditions. 

2/ Dependent on type of irrigation system used 



4-4 



TABLE 4.3 

TYPICAL CULTURAL PRACTICES 

FOR ALFALFA HAY 

PRODUCTION IN THE STUDY AREA 



1/ Crop 

Practice Alfalfa Hay 

Chisel X 

Disc X 

Plane X 

Border Preparation X 
Cover Seed X 



\_/ Practices required for crop 
establishment . 



TABLE 4.4 

SUMMARY OF IRRIGATION METHODS COMMONLY USED 

FOR FIELD CROP PRODUCTION 



Crop Irrigation Method 

Small Grain Flood, Sprinkler, Furrow 

Rice Flood 

Cotton Furrow, Sprinkler 

Saf flower Furrow, Sprinkler, Subsurface 

Sugar beet Furrow 

Field corn Furrow 

Grain sorghum Furrow 

Beans Sprinkler, furrow 

Alfalfa seedl/ Furrow, sprinkler 



V Alfalfa hay can be irrigated with all methods 
except drip. 



4-5 



TABLE 4.5 

SUMMARY OF IRRIGATION METHODS COMMONLY USED 

FOR TRUCK CROP PRODUCTION 



Crop Irrigation Method 

Tomato Drip, Sprinkler, Furrow, Sprinkler/ 

Furrow 

Onion Sprinkler, Flood 

Garlic Furrow, Sprinkler 

Potato Furrow 

Melon Furrow 

Other Sprinkler, Drip, Furrow 

vegetables 



A significant element in required irrigation management practices is 
the pre-irrigation applications required for the production of crops 
such as cotton, cantaloupes, and tomatoes. Pre-irrigation is a 
source of inefficiency where excess water is applied to bring the 
crop root zone to field capacity immediately prior to planting. 
Both cotton and cantaloupe seeds are then planted to moisture while 
tomatoes are germinated using sprinklers. Pre-irrigations are 
required for these crops since it is difficult to maintain required 
levels of soil moisture during periods of peak ET usage because of 
crop evapotranspirat ion losses and rooting characteristics. 
Experience has demonstrated that crop yield losses occur if pre- 
irrigations are not applied. Pre-irrigations for these crops are 
often highly inefficient because of the time of year and surface 
irrigation methods used to apply the water. 

Effective irrigation water management is key to producing maximum 
crop yields without degradation of soil or water resources. The 
timing and amount of application are variables directly related to 
crop water needs and the soil water holding capacity. A review of 
responses to the grower survey indicates that irrigation scheduling 
is often based on physical inspection of the soil and crop 
supplemented when available with data from neutron moisture probes, 
tensiometers , pressure bombs, crop consumptive use calculations, 
evapotranspiration models, and soil probing. If properly used, the 
data from these methods will provide growers with an effective method 
of determining crop water requirements and the need for irrigation 
water applications. 



4- 6 



Land leveling is consistently used throughout the area in an attempt 
to obtain uniform water distribution for surface irrigation. 
Shorter irrigation runs with higher flows are also being implemented 
to decrease deep percolation and achieve more uniform water 
distribution across a field. Measuring devices such as meters/ 
Parshall flumeS; etc. provide a means of determining amounts of water 
that will be applied to an area but they are currently used to a 
limited extent by growers in the study area. These measuring 
devices are not widely applied probably because of cost/ grower 
education/ and lack of perceived need. Even though tools are 
available to monitor crop water requirements and determine the need 
for irrigations/ many irrigators in the study area are inefficient 
irrigators. This occurs as a result of many factors such as: 1) 
poor management; 2) lack of technical knowledge; 3) poor irrigation 
design/ 4) insufficient capital funding/ and 5) lack of incentive to 
conserve water. 

The present trend is to install more efficient irrigation systems in 
the study area. The method of irrigation is the basis from which 
many irrigation management practices are derived. Table 4.6 
summarizes irrigated crop acreages for various irrigation methods in 
the San Joaquin Valley and California in 1972 and 1980. Total San 
Joaquin Valley irrigated acreage has increased about 12 percent 
while total state acreage has only increased about 8 percent during 
the 1972 to 1980 period. 

Furrow irrigation has increased about 19 percent in the San Joaquin 
Valley. Grower surveys indicate that gated pipe is increasingly 
used to provide greater water control when using furrow methods. 
Sprinkler and drip irrigation methods have increased at rates of 22 
percent and 92 percent during the period 1972 to 1980 in the San 
Joaquin Valley. Proper irrigation water management is probably the 
single most effective method of reducing the potentially harmful 
detrimental soil and crop effects that may be caused by over- 
irrigation in the study area. 

4.4 SALINITY AND DRAINAGE MANAGEMENT 

Some growers in the study area are effectively dealing with salinity 
and drainage problems on-farm. Salts in surface soils are commonly 
removed by leaching with high quality water during pre-irrigation . 
Similarly/ reclamation of severe salt affected areas has been 
achieved by deep leaching of the soil with good quality water. 
Maintaining acceptable soil salinity levels in the crop root zone is 
essential to achieving optimum crop production. Currently/ growers 
are attempting to accomplish this through irrigation with low- 
salinity water/ proper irrigation water management/ and subsurface 
drainage systems. 

Potential salinity problems exist where tailwater and/or subsurface 
drainage water is used to irrigate crops. Careful blending with 

4- 7 



TABLE 4.6 
SUMMARY OF IRRIGATED CROP ACREAGE BY IRRIGATION METHOD 
IN THE SAN JOAQUIN VALLEY AND CALIFORNIA 
{1,000 acres)!/ 



27 

Irrigation San Joaquin California 

Method 1972 1980 1972 1980 

Surface Irrigation 

Wild Flood - 5 210 260 

Border 2,120 1,860 3,650 3,210 

Basin 40 255 340 730 

Furrow 1,730 2,430 3,150 3,600 

TOTAL SURFACE 3,890 4,540 7,350 7,800 

Sprinkler Irrigation 

Solid Set 160 145 310 395 

Hand Move 430 565 1,120 1,035 

Mechanical Move 30 85 140 305 

TOTAL SPRINKLER 620 795 1,570 1,735 

Drip Irrigation 10 135 30 260 

Sub-Irrigation 10 40 100 125 

TOTAL ACREAGE 4,530 5,510 9,050 9,820 



\/ 1912 data from J. Ian Stewart (1975). 

1980 data from California Department of Water Resources (1983). 

2/ Aggregation of data from San Joaquin and Tulare Lake hydrologic 
study areas as defined by California Department of Water 
Resources . 



4-8 



higher quality water is necessary to achieve a suitable quality water 
for irrigation purposes and to eliminate the possibility of salt 
buildup in the root zone. 

Subsurface drainage systems are being used in the study area to 
remove excess drainage water from the soil. These systems are being 
installed at or below the water table and appear to be effectively 
reducing water table depth while crop quality and quantity are 
gradually improving. In some instances, saline subsurface drainage 
water is being used for irrigation purposes with resultant crop yield 
losses. Subsurface drainage waters are usually too saline for 
direct use on crops without blending, but blending these saline 
waters is often not practical because of the amount of low salinity 
water that must be used to reduce salinity to acceptable levels. 

Disposal of subsurface drainage water has been and continues to be a 
major problem in the area. On-farm evaporation ponds are used to a 
limited extent in areas where alternatives do not exist. About 
15,000 acres of ponds have been constructed in the study area to date; 
however, several requests have been made to increase this amount 
significantly. Water is also discharged into district drains that 
ultimately flow to the San Joaquin River for disposal. 

4.5 NET ECONOMIC RETURN FROM CROP PRODUCTION 

The profit from an agricultural operation can be defined as the 
difference between crop production income and costs associated with 
all on-farm investments and production, including the cost of 
irrigation water. Production costs include all fixed and variable 
costs including management required to grow a certain crop. The net 
farm return is based on on-farm development/production cost, crop 
yield, and commodity value. Crop production costs vary appreciably 
between different operations. Production costs typically include 
the cost of land, water, fertilizers, pesticides, labor, 
transportation, interest, and equipment depreciation. These costs 
vary between operations as result of the capability of different 
managers. Further, the time during which land was purchased 
significantly influences its cost as a result of prevailing land 
value and interest rates. Farm equipment costs may vary as a result 
of the same factors and also as a result of the size, type, and volume 
of equipment purchased. The base costs of water, fertilizers, 
pesticides, labor, and transportation do not generally vary. 
However, the ability of the farm manager to efficiently apply these 
production factors may greatly affect the overall cost. Thus, 
because of these differences in crop production costs two farms of 
identical size with the same cropping pattern and yield will likely 
return very different net profits. These two managers will likely 
view on-farm management alternatives from different perspectives as 
a result of their different management styles and economic 
situations. Crop yield will also vary between operations as a 
result of the level of management expertise and different crop 
production approaches and from the differences in soil, water, and 

4- 9 



environmental resources which occur. Crop commodity value varies 
throughout the year. Thus/ the time of sale has a significant 
determination on its final value. Further, participation in farm 
subsidy programs also influences net farm return. Based on these 
factors; the development of estimates of typical net farm or crop 
returns in the study area would likely be atypical of farming 
operations. Thus/ it is inaccurate to develop cost and benefit data 
for alternatives other than to address general ranges that may occur. 

Developing economic data to estimate net returns on an agricultural 
operation in the study area is of little value because of the 
variability between similar operations. A more logical approach is 
to evaluate costs and benefits on an individual farm or ranch basis. 
Because of economic differences between operations, no one 
alternative or set of alternatives can be applied to solve the 
problem. More important than a general profit or loss figure is an 
understanding that commodity values, crop production costs, 
management and overhead cost, and other direct and indirect costs 
will affect net returns on a yearly basis. Further, a .carefully 
conceived incentive program may be required to assist in the 
implementation of feasible management alternatives. 

4.6 EXISTING IRRIGATION AND DRAINAGE MANAGEMENT PROGRAM 

Existing on-farm irrigation and drainage management programs in 
California have been directed toward water conservation. In the San 
Joaquin Valley, an important goal is to reduce groundwater 
overdraft . 

The water conservation programs of public agencies are primarily 
based on computer irrigation scheduling approaches dependent on 
crop, soil, and climatic data. These include the USBR Irrigation 
Management Service (IMS), which was renamed the Water Management and 
Conservation (WMC) program (Lyford and Schild, 1981), and the 
University of California Irrigation Management Program (IMP) 
(Fereres et al . , 1981). In addition, the California Department of 
Water Resources funded the development of the California Irrigation 
and Management Information System (CIMIS) by the University of 
California to monitor and disseminate current weather data for use in 
irrigation scheduling (Snyder et al., 1985). CIMIS was recently 
incorporated with the IMP program by the Office of Water Conservation 
(DWR). More recently, an irrigation measurement and evaluation 
program was established by the California DWR using mobile 
laboratories located in agricultural districts around the state. 
Other programs have been developed by irrigation districts in the 
last several years with the assistance of the USBR. Private 
irrigation consulting services have also been established in 
California, largely using methods developed by the USBR. These 
programs are generally described in the following sections. 

The larger sophisticated growers in the study area have a staff 
person or consultant who provides irrigation scheduling expertise. 



4- 10 



These individuals often rely on these services for support. The 
smaller, less sophisticated operations typically do not use these 
services because of cost and lack of education on the technical 
aspects and benefits. Based on the grower survey and experience, 
less than 25 percent of the growers in the study area presently use 
these services. 

4.6.1 The Irrigation Management Service (USER) 

The IMS program was originally based on a computerized water budget 
method developed by Marvin Jensen (Jensen, 1969: and Jensen et al . , 
1971), USDA/ARS. The IMS program was first used in Idaho in 1969 and 
was initially demonstrated in California in the Westlands Water 
District in 1972. The federal government assisted the district in 
developing the program. The program contract period was three years 
after which the program was performed by district staff (Lyford, 
1977). To date seven California irrigation districts have 
participated in the program. 

4.6.2 Irrigation Management Program (University of California) 

Because of the slow acceptance of the IMS program, which probably 
resulted from a perceived lack of need, (Liss et al . , 1981) the 
University of California contracted with the DWR to develop an 
irrigation scheduling system based on soil, crop, and climatic data 
readily available in California (Fereres et al., 1980 and 1981). 
Using these data a computer program applies a water budget method to 
determine the irrigation schedule for the season. Information is 
made available to growers and consultants through computer generated 
leaflets . 

4.6.3 California Irrigation Management Information System 
(CIMIS) 

The CIMIS program was developed by the University of California under 
contract to the DWR. CIMIS was designed to: 1) gather current 
climatic data from weather stations located in agricultural 
districts in order to determine crop water requirements on an on- 
going basis and 2) disseminate this information to the public for use 
in irrigation scheduling (Snyder et al., 1985). In conjunction with 
this program, an "Irrigation Scheduling Guide" was published 
(Fereres and Puech, 1981). Recently this program was incorporated 
into the IMP by the DWR. 

4.6.4 Mobil Agricultural Water Conservation Laboratories 

With the increasing use of irrigation scheduling services, there 
became a greater need to evaluate irrigation system performance and 
measure irrigation application rates in order to realize the full 
benefits from the scheduling services available. In response to 
this need, the El Dorado Irrigation District and the Pond-Shaf ter- 
Wasco Resource Conservation District (RCD) contracted with the DWR 



4- 11 



to conduct irrigation system evaluations in order to improve 
irrigation efficiency. Local USDA Soil Conservation Service (SCS) 
personnel provided technical support. This initial work resulted 
in the creation of the "Mobile Water Conservation Laboratories" 
staffed by SCS personnel and student assistants (Fry, 1985). 
Technical supervision is provided by Dr. Charles Burt of California 
Polytechnic State University, San Luis Obispo. Currently, there 
are five mobile labs with one each in Kings, Kern, San Diego, 
Coachella, and Ventura Counties (Suzanne Butterfield, Chief, Office 
of Water Conservation DWR, personal communication). Original 
funding for the mobile lab program was provided by the State Water 
Resources Control Board from the 1978 Proposition 2 State Assistance 
Program Grant (SAP Grant). The program is currently funded by DWR. 
California Polytechnic State University at San Luis Obispo provides 
an Irrigation System Evaluation Program in cooperation with the DWR. 

In November, 1985, the DWR requested an appropriation of SAP grant 
monies to fund a westside drainage reduction program. Included in 
the program was funding for two additional mobile labs for the 
Westside RCD and Los Banos RCD (California DWR Office of Water 
Conservation memorandum, November, 1985). 

4.6.5 Other Irrigation/Drainage Management Services 

The soils and irrigation specialists affiliated with the University 
of California Cooperative Extension provide on-going guidance for 
soil and irrigation management problems. These individuals are 
associated with local county farm advisor's offices in each county 
included in the study area. Area specialists located at either UC 
Davis or UC Riverside are also available for periodic consultation. 
The SCS irrigation and drainage specialist also provides 
consultation on problems related to irrigation and drainage. 
Assistance is also available through many of the resource 
conservation districts in California. The RCD is the primary 
contracting agent for the DWR mobile lab program. 

Some water agencies provide various levels of service to their 
growers on irrigation management and scheduling. For example, 
Westlands Water District (WWD) was assisted by the USBR in creating 
an IMS program. Subsequently, WWD developed its own water 
conservation and management program (Westlands Water District, 
1985) for use by growers in the district. 



4- 12 



SECTION 5 
SURVEY OF RECENT AND ON-GOING RESEARCH ACTIVITIES 

5.1 AREAS OF INVESTIGATION 

Boyle conducted a comprehensive review of published and unpublished 
literature on a wide range of possible on-farm management 
alternatives that would directly or indirectly effect a reduction of 
subsurface drainage flows from irrigated lands. In addition, on- 
going research activities in government agencies, universities, and 
other research groups were reviewed. 

Criteria for reviewing past and present research programs were based 
on whether the research objectives were related to the following 
possible on-farm management practices: 

o Improving on-farm conveyance efficiencies. 

o Improving irrigation application efficiencies. 

o Using more efficient irrigation systems. 

o Improving irrigation scheduling. 

o Reusing drainage waters for irrigation. 

o Using a saline, shallow water table to meet a portion 
of the crop water requirement. 

o Reducing deep percolation by using different crop management 
practices . 

o Using salt/boron tolerant crops. 

o Using agroforestry technology to lower the water table. 

o Modifying subsurface drainage design to control or minimize 
drainage flows. 

o Installing on-farm treatment/storage facilities for 
drainage waters. 

Additional research related to the effects of various management 
practices on: (1) soil properties and drainage water quality; and 
(2) economic and institutional constraints to implementation were 
reviewed. Recent and on-going research programs and unsolicited 
aj-ternative on-farm management proposals are also summarized. 



5- 1 



5.2 SOURCES OF INFORMATION 

The types of materials obtained included periodical literature, 
conference proceedings/ books/ monographs, review articles, 
bulletins, pamphlets, bibliographies, and notes from meetings and 
conversations. Those materials cited in this report are also 
referenced in the Bibliography section (Appendix A). A keyword 
index system is provided in Appendix B to facilitate retrieval of 
references by topic. 

5.2.1 Periodical Literature 

Several important research journals were identified and their tables 
of contents reviewed for at least the 1975-1985 period to identify 
relevant publications. This approach did not preclude inclusion of 
references published earlier if cited in more recent publications. 
Most of the journals reviewed in detail as summarized in Table 5.1 
were published in the United States. 

5.2.2 Conference Proceedings 

Material from conference proceedings was also reviewed. 
Information was obtained from the annual proceedings of specialty 
conferences of the Irrigation and Drainage Division of the American 
Society of Civil Engineers and regular conferences of the American 
Society of Agricultural Engineers. Data were also gathered from the 
proceedings of the International Commission on Irrigation and 
Drainage . 

Two important conferences sponsored by the U.S. Environmental 
Protection Agency (U.S. EPA, 1972 and Law and Skogerboe, 1977) were 
held on managing irrigated agriculture to improve water quality. 

An international symposium on research needs for on-farm water 
management, held in Park City, Utah, in 1973, was sponsored by the 
US/AID (1974). Another International Conference titled "Managing 
Saline Water for Irrigation" was sponsored by the Subcommission on 
Salt-Affected Soils, International Soc. of Soil Science (Dregne, 
1976). The "Second Inter-American Conference on Salinity and Water 
Management Technology" was held in Juarez, Mexico in 1980. 

Another relevant international seminar titled "Land and Stream 
Salinity" was held in Australia and primarily concerned the 
occurrence of salinity problems in recently developed agricultural 
lands (Holmes and Talsma, 1981). In California, a symposium on 
"Agricultural Waste Waters" was held in Davis in 1966 (Doneen, 1966). 
A conference on salt and salinity management was held in Santa 
Barbara in 1976 (Anonymous, 1976). A workshop on agricultural water 
conservation was held in Fresno in 1980 (California Water 
Commission, 1982). A salinity and drainage workshop was held in 
Fresno in January, 1986. 



5- 2 



TABLE 5.1 
SUMMARY OF PERIODICALS EVALUATED FOR THE ON-FARM 
AGRICULTURAL MANAGEMENT STUDY 



Name of Periodical 



Advances in Irrigation 

Agricultural Engineering 

Agricultural Water Management 

Agronomy Journal 

American Society of Agricultural Engineers/ Transcript 

American Society of Civil Enginers, Proceedings 

Australian Journal of Agricultural Research 

Australian Journal of Soil Research 

California Agriculture 
Crop Science 

Hilgardia 

Irrigation Science 

Irrigation and Drainage Abstracts 

Israeli Journal of Agricultural Research 

Journal of Agricultural Research 

Journal of American Society of Horticultural Science 

Journal of Environmental Management 

Journal of Environmental Quality 

Journal of the Irrigation & Drainage Division, ASCE 

Journal of Soil Science 

Journal of Soil and Water Conservation 

Journal of Water Resources Research 

Soil Science 

Soil Science Society of America Journal 

Water Resources Bulletin 



5- 3 



5.2.3 BookS/ Monographs/ and Reviews 

Several important books and monographs with discussions of 
technologies applicable to drainage water reduction were 
identified. These included two American Society of Agronomy (ASA) 
Monographs titled "Irrigation of Agricultural Lands" edited by Hagan 
et al. (1967) and "Drainage for Agriculture" edited by Van 
Schilfgaarde (1974). In the first monograph, articles related to 
irrigation scheduling, irrigation management, and irrigation 
systems were reviewed. In the second monograph, articles on salt 
and water movement, quality of drainage water, and water management 
systems were reviewed. 

Another publication by the ASA titled "Limitations to Efficient 
Water Use in Crop Production" edited by Taylor et al. (1983) was 
reviewed for information on crop and soil management as it related to 
reducing drainage. 

For information on improving irrigation efficiency through the 
design and operation of irrigation systems, publications edited by 
Jensen (1980) and Pair et al . (1983) were reviewed. Publications on 
the quality of irrigation water were those by Shainberg and Oster 
(1978) and Ayars and Westcot (1985). Books published by the 
University of California Press include those edited by Engelbert 
(1979, 1982, 1984). A book of papers from a conference on plant 
tolerance to salinity was edited by San Pietro (1982). Yaron et al. 
(1973) edited a book titled "Arid Zone Research". 

5.2.4 Reports to Public Agencies 

Reports to public agencies gathered from a variety of sources, 
included discussions of the following general topics: 

o Improving irrigation efficiencies with new irrigation 
techniques or management practices. 

o Improving irrigation scheduling. 

o Crop response to salinity. 

o Cropping patterns. 

o The water quality, geology, hydrology, and drainage of the study 
area . 

o Water conservation. 

5.2.5 Personal Communication 

Many individuals and agencies were contacted in an effort to obtain 
information. These individuals included personnel from: 



5- 4 



o Many of the water agencies in the study area. 

o Growers in the study area. 

o University of California, Davis and Riverside. 

o University of California Cooperative Extension. 

o USDA/ARS, Fresno, CA. 

o USDA Water Conservation Laboratory, Phoenix, AZ . 

o USDA/ARS Fort Collins, CO. 

o USDA Salinity Laboratory, Riverside, CA. 

o USDA, Soil Conservation Service 

o California Department of Water Resources. 

o California State Water Resources Control Board. 

o California Department of Food and Agriculture. 

o Center for Irrigation Technology, CSU-Fresno. 

o Alliance for Responsible Water Policy. 

o Land Preservation Association. 

o Environmental Defense Fund. 

o UN/FAO Commission on Irrigation and Drainage. 
5.2.5 Publication Lists 
Publications lists were obtained from the following: 

o USDA Salinity Laboratory (Riverside, California); 

o USDA Water Management Research Laboratory, (Fresno, 
California ) ; 

o USDA Water/Conservation Research Laboratory (Phoenix, 
Arizona ) . 

o US Environmental Protection Agency, Robert S. Kerr 
Environmental Research Laboratory (Ada, Oklahoma) 

o University of California Water Resources Center (California 
Water Resource Center, 1984). 



5- 5 



o University of California/ Agricultural Experiment Station. 

o University of New Mexico/ Agricultural Experiment Station. 

o Utah State University/ Agricultural Experiment Station. 

o University of Arizona/ Agricultural Experiment Station. 

o California DWR (California Department of Water Resources/ 
1970/ 1974/ 1979, 1984). 

5.2.7 Published Bibliographies 

Several particularly relevant bibliographies/ with and without 
abstracts/ were reviewed during the course of the literature search. 
These included "Irrigation Efficiency: A Bibliography" and 
"Irrigation Return Flow: A Bibliography" published by the Office of 
Water Research and Technology (OWRT/ U.S. Dept. of Interior/ 1973 
and 1975). Since the OWRT data base is now included in the National 
Technical Information System (NTIS) data base system/ other OWRT 
bibliographies were searched through NTIS. An important 
bibliography published by the NTIS is titled "Soil Salinity: 
Irrigation Practices and Effects on Crops and Groundwater" (1977- 
1985 U.S. Department of Commerce/ 1985) which includes citations 
with abstracts from the Selected Water Resource Abstracts (SWRA) 
data base. 

Also evaluated was the series titled "Selected Irrigation Return 
Flow Quality Abstracts" published annually by the Robert S. Kerr 
Environmental Research Laboratory/ Ada/ Oklahoma (Skogerboe/ et 

al./ 1972/ 1973/ 1974/ 1975/ ) as a research report for the 

Office of Research and Development/ US/EPA. 

Another important bibliography which includes records from the 
National Agricultural Library iS/ "Plant Response to Salinity" 
published in 1978 and a supplement published in 1985 (USDA, 1978 and 
1985). 

5.2.8 On-Line Computer Searches 

Several bibliographic data bases are currently available to the 
public that contain reference material related to on-farm management 
alternatives/ including reduction of agricultural drainage/ reuse 
of brackish water for irrigation/ tolerances of crops to salinity/ 
and improving irrigation efficiency. These include the following: 

o AGRICOLA (Agricultural On-Line Access): This data base is 
primarily an index of the holdings of the National Agricultural 
Library of the USDA. It consists of records of journal 
articles/ monographs/ theses/ and technical reports from all 
over the world in agricultural and related fields. 



5- 6 



o CRIS/USDA (Current Research Information System/USDA) : This is 
a data base of current research in agriculture and related fields 
sponsored or conducted by the USDA Abstracts of citations which 
includes research objectives, study approach/ and accomplish- 
ments to date. 

o NTIS (National Technical Information Service): This data base 
is produced by the US Department of Commerce and contains records 
of US government sponsored research, development, and 
engineering reports originating primarily from the US 
Department of Energy, US Department of Defense, and National 
Aeronautics and Space Administration, but also including 
material from other governmental agencies. Also included are 
unpublished materials originating outside the United States. 
Published searches from this data base and others are available 
from NTIS. 

o RESOURCES ABSTRACTS: This data base, produced by the US 
Department of Interior, Office of Water Research and Technology 
(OWRT), contains records, including abstracts, of journal 
articles, monographs, reports, patents, conference proceedings, 
court proceedings, etc., on water-related topics. 

o GEOREF: Produced by the American Geological Institute (AGI), 
this data base covers technical literature in the fields of 
geology and geophysics from all over the world. 

o CAB ABSTRACTS: This data base includes all records in journals 
published by the Commonwealth Agricultural Bureau (CAB). These 
include sixteen abstracting journals that contain records from 
more than 8,500 serial journals from around the world. 

The above data bases can be accessed at least in part by several on- 
line retrieval services, including DOE/RECON, BRS Information 
Technologies, DIALOG, Mead Data Central, NLM (National Library 
Medium), Telesystems Questel, and SDC (System Development 
Corporation) Orbit. DIALOG has access to all of the above data 
bases . 

The on-line retrieval services offer direct dial access to their 
systems over a terminal or a microcomputer with terminal-emulation 
capabilities. Data base records can be identified through boolean- 
logic searches and can be down loaded to a printer or to disc memory 
for later review and editing. Charges vary depending on the on-line 
service used, but are generally based on connect times and off-line 
print or on-line type (includes downloading to another device, i.e. 
diskette, etc.) rate per record. The DOE/RECON on-line retrieval 
system is primarily available to the Department of Energy and its 
contractors and contains about 50 bibliographic and non- 
bibliographic data bases containing energy related information. 
The on-line data retrieval services as well as many of the data bases 
can be accessed through one of several packet-switching networks 

5- 7 



including TELENET, TYMNET, DIALNET, UNINET, DATAPAC, PSS, and 
TRANSPAC. 

5.3 ORGANIZATION OF INFORMATION 

In order to catalog journal articles, conference proceedings, 
monographs and books, reports, theses, bibliographies, etc., a 
database management system (DBMS) was installed on an IBM Personal 
Computer XT for managing bibliographic records. 

5.4 RECENT AND ON-GOING RESEARCH PROGRAMS 

Information summarizing drainage-related research was obtained from 
several sources. Water/drainage related on-going research 
conducted in the University of California system including the 
Agricultural Experiment Station is summarized in periodically 
updated reports of the Water Resources Center (California Water 
Resources Center, 1984). Included in these reports are project 
titles, names of principal investigators and affiliation, sources of 
funding, amount and period of award, and a project summary. A 
listing of research projects developed in July, 1985 redirected 
toward environmental problems in the San Joaquin Valley related to 
salinity, drainage, selenium, and other toxic constituents was 
prepared by the Division of Agricultural and Natural Resources of the 
University of California. 

Information summarizing current and recently completed research on 
agriculture and related fields sponsored or conducted by the USDA is 
available through the Current Research and Information System 
(CRIS). Records are kept on a publicly available computerized data 
base (CRIS/USDA) and include the following information: project 
title, investigators, location, performing organization, period, 
and an abstract which summarizes project objectives, approach, 
progress, and publications. 

Current research activities related to reducing agricultural return 
flows are largely centered in California. Research is being 
conducted primarily by the University of California and the USDA 
Agricultural Research Service. Funding sources include state 
monies, Kearney Foundation of Soil Science grants to UC researchers, 
in-house UC agricultural research funds, and federal Hatch Act funds 
for Land Grant Universities. A summary of on-going projects, 
principal investigators, locations, and funding sources is shown in 
Table 5.2. Major programs directed toward the reduction of 
agricultural subsurface drainage flows are discussed in the 
following sections. 

5.4.1 The U.S. Environmental Protection Agency Irrigation 
Return Flow Program 

Concern for the nation's water quality resulted in the passage of the 
Water Quality Act of 1965 (PL89-234) and the Clean Water Restoration 



5- 8 



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Act of 1966 (PL89-753) which established a national policy for the 
prevention, control/ and abatement of water pollution (Law, et al . , 
1972). In 1970 the EPA began its irrigation return flow research and 
development program (now the irrigation and crop production research 
program), directed by James P. Law and based at the Robert S. Kerr 
Water Research Center (now the Robert S. Kerr Environmental Research 
Laboratory) in Ada, Oklahoma. 

In May, 1972, an EPA conference on managing irrigated agriculture to 
improve water quality was held which focused primarily on: 1) 
identifying and describing irrigation return flow quality problems 
and 2) describing research necessary to develop solutions to 
problems of irrigation return flow quality (Law, 1977). The 
following October, Congress passed the Federal Water Pollution 
Control Act Amendment of 1972 (PL 92-500) which, among other items, 
mandated that water degradation from agricultural activities be 
controlled. It also provided in Section 101b that it was the policy 
of Congress to support and aid research relating to the prevention, 
reduction, and elimination of pollution and to provide federal 
technical service and financial aid to state and interstate agencies 
and municipalities in connection with the prevention, reduction, and 
elimination of pollution (Law and Hornsby, 1977). 

With the Congressional mandate of PL 92-500 and increasing problems 
of irrigation return flows in western waters, the irrigation return 
flow research and development program supported extensive research 
in the next several years directed primarily at defining appropriate 
technologies for alleviating water quality problems from irrigated 
agriculture (Law, 1977). 

The result of a great part of this research was reported in a 
conference held at Colorado State University in 1977 (Law and 
Skogerboe, 1977). Much of the research related to on-farm 
management practices to reduce subsurface drainage flows was 
conducted in the Colorado River basin in Grande Valley, Colorado; in 
Ashley Valley, Utah; and in the Wellton-Mohawk Irrigation District, 
Arizona. Additional studies were conducted in the Mesilla Valley, 
New Mexico. Funding for the irrigation return flow studies was 
significantly reduced after 1977 and remaining efforts were directed 
toward implementing management guidelines based on research 
results . 

The research on reducing the volume of drainage flows from the 
Wellton-Mohawk Irrigation District was initiated primarily in 
response to an agreement between the United States and Mexico signed 
in 1973 which guaranteed a minimum standard of water quality for 
waters from the Colorado River entering Mexico (Holbert, 1977). A 
discussion of the research programs performed at the Wellton-Mohawk 
Irrigation District was held by Krull and Clark (1977). 

Research conducted in the San Joaquin Valley was largely oriented 
toward evaluating bio-engineering controls on drainage water 



5- 12 



quality; including nitrogen removal technologies and the planned 
construction of a valley-wide master drain. Little effort has been 
directed toward evaluating on-farm management practices to reduce 
drainage flows. 

In other parts of the United States; most research on drainage 
problems has focused on management practices that would reduce 
surface runoff rather than subsurface drainage flows (Schaller and 
Bailey, 1981). 

5.4.2 USDA Agricultural Research Programs 

Drs. James Ayars and Glenn Hoffman with the USDA Water Management 
Research Laboratory in Fresno are conducting research on the effects 
of water quality and irrigation application uniformity on the yield 
of row crops. In addition, Dr. Ayars is testing irrigation 
management concepts in a field with subsurface drain lines. This 
research is necessary to develop operational concepts for using 
shallow groundwater to satisfy a portion of the crop water 
requirement. Dr. Claude Phene and others are investigating the 
effect of a saline water table on row crops and the use of drip 
irrigation for processing tomatoes. Some of the most extensive work 
using saline drainage waters for irrigation of row crops is being 
conducting by Dr. James Rhoades of the USDA Salinity Laboratory, 
Riverside in the Imperial Valley and in the Lost Hills area of the San 
Joaquin Valley. In this work, the effect of irrigation water 
salinity on crops is being determined for different crop growth 
stages. Crops are more salt tolerant during some growth stage's 
which allows irrigation with saline water without yield loss. 
Soluble salt accumulations in the soil profile are leached during 
irrigations with good quality water. This approach offers an 
opportunity to reuse drainage waters without subsequent yield loss 
or the need to plant salt tolerant crops. In Berkeley, Drs. 
Zellerman and Handleman are investigating the economic feasibility 
of using surge flow systems under various configurations. This will 
provide base data necessary to make comparisons with existing 
irrigation system costs. At a USDA research laboratory in Ft. 
Collins; CO.; E. G. Kruse and D. F. Heermann are revising irrigation 
scheduling procedures to account for water use by crops from shallow 
saline water tables. Extensive research on salinity and boron 
tolerance of various agricultural and horticultural crops has been 
continuing for many years at the USDA Salinity Laboratory, 
Riverside. Principal investigators are Dr. Eugene Maas and Dr. 
Leland Francois. 

At the USDA Water Conservation Research Laboratory in Phoenix, AZ , 
continuing work on level basin irrigation is being conducted by A. R. 
Dedrick. In addition, D. A. Buck is developing new technologies for 
drip irrigation and R. J. Reginato is refining irrigation scheduling 
based on remote sensing techniques. 



5- 13 



5.4.3 University of California Research Programs 

There are several programs investigating the potential for reusing 
agricultural drainage waters for supplemental irrigation in the 
University of California system. At the Westside Field Station near 
Five Points/ California; the effects of irrigation with drainage 
waters on processing tomatoes are being investigated by research 
groups headed by Steve Gratton and Don May. Another study on the 
effect of irrigation waters of different salinities on typical crops 
is being conducted by Dennis Rolston at UC Davis. In the Imperial 
Valley/ Frank Robinson is evaluating the effect of saline waters on 
the growth of various trees/ crops/ and native vegetation. These 
studies related to irrigation with saline water are important 
because crop response to irrigation with saline water must be 
quantified to develop drainage water reuse plans. At the Westside 
Field Station near Five Points/ Ck, Pamela Elam-Wenzel is 
investigating the effect of water application rates on the growth of 
different species of Eucalyptus. Agroforestry may be used to draw 
down the perched water table. Information related to water use and 
crop yield under different moisture regimes is needed for economic 
evaluations . 

At UC DaviS/ Dr. Miguel Marino is investigating the optimal sizing of 
subsurface drainage systems for cotton and is developing a 
comprehensive water management model. He is also investigating 
optimization techniques to design irrigation systems. 

University funding for investigating newer more efficient 
irrigation methods is somewhat limited. Drs. Cannell and Letey of 
the University of California Riverside are doing a laboratory study 
to evaluate the basic principles behind the better uniformity of the 
surge irrigation system. In addition/ comparisons of water 
application uniformities between surge and continuous flow 
irrigation systems are being made by Dr. Wallender and Del Henderson 
of UC Davis. Further investigation of irrigation using saline 
groundwater with low volume spray and sprinkler irrigation systems 
of sorghum and cotton is being conducted in the Imperial Valley by Dr. 
Frank Robinson of UC Davis. 

A cooperative effort between Dr. L. W. Stolzy of UC Riverside and Drs. 
Shalhevet and Sinai of Israel on management policies and design 
principles for irrigation systems using more than one source of 
irrigation water of different qualities is being funded by the Bi- 
national Agricultural Research and Development (BARD) program. 

Dr. Donald Grimes (UC Extension/ Parlier/ California) is continuing 
his investigation into the contribution of the shallow perched 
saline water table to the water requirements for row crops. 

Dr. Rolston/ UC Davis recently investigated the response of crops to 
temporal and spatially variable soil salinity profiles. Work on 
developing salt tolerant genotypes among commonly grown crops in 



5- 14 



California has been continuing for many years under the direction of 
Dr. Emanuel Epstein at UC Davis. Dr. Andre Lauchli/ also of UC Davis 
is evaluating species of crucifers under saline and minimum water 
regimes . 

5.4.4 Other Research Programs in California 

General research on irrigation technologies/ largely privately 
financed, is being carried out at the Center for Irrigation 
Technology at California State University/ Fresno. Some of the 
efforts have been directed toward linear move systems and subsurface 
drip systems for row crops. The current director is Dr. Ken Solomon, 
formerly with the USDA Salinity Laboratory, Riverside. California 
Polytechnic State University/ San Luis Obispo has an active 
agricultural engineering program conducting irrigation related 
research. Binnie & Partners and Harza Engineering are conducting 
research on methods of selenium removal from drainage waters. 
Although not a management alternative, it may be possible to use 
these techniques as part of an on-farm treatment system. 

5.4.5 Other Research Programs Outside California 

Outside California/ Dr. G. V. Skogerboe of Colorado State University 
has been evaluating best management practices for reducing the salt 
load of drainage waters from irrigated lands. In Texas, Dr. J. Moore 
(Texas A & M) is investigating water use efficiency under various 
water management systems. Low energy precision application (LEPA), 
pivot systems, trickle irrigation, and surge flow systems are being 
compared. In North Dakota, Dr. Al Benz is investigating water 
management techniques that include improving irrigation efficiency 
of saline and sodic strip mine spoils. 

5.5 RESEARCH PROPOSALS RELATED TO THE SAN JOAQOIN VALLEY 
DRAINAGE PROBLEM 

Proposals discussed in this section were primarily directed to or 
channeled through the Interagency Drainage Study Program to Boyle 
Engineering Corporation (Fresno office). Proposals originated from 
federal agencies and the private sector. 

Study plans submitted by agencies of the USDA Agriculture Research 
Service are summarized in Table 5.3. Proposals that include studies 
of on-farm management alternatives are those submitted by Glenn 
Hoffman, James Ayars and James Rhoades. Other projects, although 
meritorious, are not directly related to this study and are not 
further discussed. To the extent that biochemical removal of 
selenium may be incorporated into on-farm drainage ponds, proposals 
by the Lawrence Berkeley Laboratory may be of interest (see Table 
5.4). Research proposals related to reverse osmosis and other 
methods of desalinating drainage waters are beyond the scope of this 
study. 



5- 15 



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5-16 



TABLE 5.4 
RESEARCH PROPOSAL FROM THE LAWRENCE BERKELEY LABORATORY 



Project 
Title 



Objectives 



Geochemical Characterization Characterize the existing chemical contamination 



& Evaluation of Remedial 
Measures for Kesterson 
Reservoir & Upstream 
Water Treatment 



Principal 
Investigators 

Oleh Wevers/ Arthur White; 
& T. Narasimhan 



of water & biosphere at Kesterson Reservoir &/ 
based on this information, develop specific plans 
for remedial action. A two year program with 2 
phases is proposed. The first phase would involve 
the first 3 tasks & the second phase the second 
3 tasks: 



1) Studies defining mechanisms controlling con- 
taminant distributions & mobilities in water 

& sediments of the reservoir. 

2) Studies to characterize transport of Se 
through the ecosystem, & to determine how the 
ecosystem affects geochemistry of reservoir. 

3) Chemical analysis of water & sediments, to 
describe inorganic & organic speciation of 
selenium & other trace constituents. 

4) Geochemical modification of Kesterson 
Reservoir to remove selenium from water & 
further isolate selenium in reservoir bottom 
sediments. 

5) Evaluation of 2 water treatment processes to 
remove Se from drainwater. 

6) Evaluation of possibilities for ultimate dis- 
posal of selenium recovered from water. 



5-17 



Several proposals have been submitted to the USER by private 
individuals and organizations (See Table 5.5). Three proposals 
suggested growing water hyacinths in evaporation ponds with the 
objective of removing toxic metals or selenium by plant absorption. 
In addition/ Mr. Zapatini suggested investigating the ability of 
poplar trees to act as filters to remove heavy metals from soils. 
Another proposal suggested the use of phreatophy tes to reduce the 
volume of waste water (Harvey/ Stanley & Assoc., Inc.). Similarly 
Mr. Hunt proposed growing eucalyptus trees to dry up swampy areas. 
Eucalyptus could then be used as a fuel source. Two proposals 
suggested the application of soil amendments. 

Mr. Pfeifer suggested the addition of an iron sulfide material to the 
soil or water to chemically bind certain forms of selenium. Another 
proposal was to add an organic material to the soil to reduce the 
salinity. In addition/ JM Lord/ Inc./ submitted a proposal to 
inject methanol into the soil and drain lines. Methanol would then 
promote the growth of anaerobic bacteria which would in turn cause 
the reduction and fixation of selenium. 

Two companies proposed to improve irrigation management by employing 
soil-moisture determining techniques marketed by their respective 
companies (Inform and Xerosystems/ Inc.). 

The last proposal/ submitted by Ventura Manufacturers/ was to use 
transplants to shorten the growing season. The elimination of the 
germination and early seedling stage of growth in the field would 
reduce the need for pre-irrigat ion during a stage of growth when root 
systems are insufficient to use the available water supply. 

5.6 GROWER INTERVIEWS 

Further information is required to determine the feasibility of 
implementing many of the proposed alternatives. The approach used 
to perform this study could be considered flawed without grower 
involvement since irrigators in the federal and state water service 
areas could have input into the identification of feasible 
agricultural management alternatives or in providing data needed for 
evaluation. Thus/ a grower interview format was developed to enable 
irrigators to provide needed involvement for the identification of 
potential alternatives and to collect additional data. Based on 
guidelines from the Interagency Study Team/ the goal was to interview 
about 70 to 85 irrigators in the CVP-Delta Mendota and San Luis 
service areas and about 30 to 40 in the State Water Project service 
area . 

The grower survey format was developed in conjunction with the 
preliminary list of on-farm agricultural management alternatives. 
The survey was developed to gather information needed to evaluate the 
potential alternatives and to determine how irrigators are currently 
dealing with on-farm subsurface drainage problems and drainage flow 
disposal. The irrigators were also asked to identify potential 

5- 18 



TABLE 5.5 
SUMMARY OF RESEARCH PROPOSALS 
FROM THE PUBLIC SECTOR 



Principal Investigators 



Objectives 



Lewis Bakser 
Lewis Bakser/ Inc. 
2829 Broad Street 
Philadelphia, PA 19132 



To use water hyacinths in waste water lagoons to 
absorb heavy metals from these waters and then 
harvest these plants for chemical recovery of 
heavy metals. 



Robert L. Green To study the use of water hyacinths to remove 

Robert L. Green Landscaping selenium from the Kesterson ponds. 
3141 Stanley Blvd. 
Lafayette, CA 94549 



Craig Jacobson 
Hydrosense Engineering 
P. 0. Box 1741 
Fair Oaks, CA 95628 

G. E. Simmers 

Brenda Way 

Carson city, NV 89701 

Gail Richardson 

Associate Director 

INFORM 

Park Avenue South 

New York, N.Y. 10016 

Buel B. Hunt 
2058 Sonoma 
Redding, CA 96001 

George Zappettini 
Zappettini Company 
17844 Yosemite Road 
Sonora, CA 95370 

Earl M. Wyatt, President 
XEROSY STEMS, INC. 
Camino Vida Roble 
Suite L 
Carlsbad, CA 92008 



To use an aquaculture system to refine water from 
water hyacinth tanks prior to reusing this water 
for irrigation. 



Polluted water reclaimed by planting water 
hyacinth plants. 



To establish an irrigation scheduling method which 
used gypsum blocks. 



To use salt tolerant species of Eucalyptus to "dry 
up the Kesterson area and utilize inmates in the 
same manner?" 

To investigate the ability of poplar trees to act 
as living filters in soils to remove potentially 
hazardous heavy metals. 



To use XEROSYSTEM's Moisture Analyzer irrigation 
control devices to refine watering cycles to 2270 
prevent water overflow to Kesterson and nnaintain 
crop yield. 



5- 19 



Table 5.5/ continued 



Principal Investigators 



Objectives 



Hal Pfeifer 
P. 0. Box 281 
Lovelock; N.Y. 



89419 



To incorporate crushed (<l/4" mesh) iron sulfide 
minerals into the soil during cultivation to 
chemically bind Se in the soil and prevent its 
leaching. 



Paul Li Hard 

Leorose-Stacy 

P. 0. Box 864 

San Jacinto, CA 92383 



To apply an organic material containing trace 
elements to soils to reduce soil salinity. 



Mike Day 
J.M. Lord, Inc. 
N. Fulton Ave. 
Fresno, CA 93701 



To fix selenium in the soil by reducing soluble 
selenate. 



John T. Stanley 
Stanley Assoc. 
906 Elizabeth Street 
P. 0. Drawer E 
Alviso, CA 95002 



To conduct a "feasibility study on the use of & 
phreatophytes in conjunction with the proposed 
evaporation pond system. " 



Alvin F. Aggen, President 
VENTURA Manufacturing & 

Implement Co. 
1255 Commercial Avenue 
P. 0. Box 1069 
Oxnard, CA 93032 



To use transplants instead of seeds to reduce crop 
water to reduce crop water requirements, and thus 
conserve irrigation water and reduce drainage. 



Fred Marx, Ph.D. 
Hydro Sciences 
27324 Camino Capistrano 
Laguna Niguel, CA 92677 



Apply Condor 55 Soil Stabilizer to seal tile 
drains, fix selenium in the soil and restore the 
soil. 



Emanuel Idelovitch 
Consulting 
Engineers, Ltd. 



To apply a soil-aquifer Tahal treatment for 
disposal /re use of agricultural drainage waters. 



5- 20 



solutions to the subsurface drainage problem 
constraints that impede their implementation. 



and identify 



Boyle developed a draft of the grower interview format using comments 
provided by the Interagency Study Team. The draft was then tested in 
the field to evaluate its completeness and the responses obtained to 
the questions. The survey document was mailed to selected 
irrigators in the study area who farm in existing or potential 
drainage problem areas. 

A number of private and public agencies (See Table 5.6) were 
contacted to request their assistance in identifying potentially 
cooperative irrigators who would likely respond to the grower 
survey. A list of 164 potentially cooperative irrigators was 
developed. Boyle attempted to contact these irrigators by 
telephone to explain the purpose/objectives of the project and to 
elicit their cooperation in responding to the grower survey. Boyle 
was able to speak with 125 irrigators/ 116 of whom indicated their 
willingness to cooperate. Copies of the grower survey were then 
sent to these individuals along with a cover letter explaining the 
purpose/objectives of the study. The grower survey was also mailed 
to the 39 irrigators whom Boyle was unable to contact. A total of 64 
responses was received. 

The response to the grower survey was much less than anticipated. 
Further/ many of the grower responses to the survey were incomplete. 
The low response may be related to the comprehensive questions and 
length of the survey. However/ conversations with selected 
individuals who later decided not to respond indicate frustration 
with the Department of Interior and lack of confidence in their 
ability to solve drainage problems as being reasons for not 
completing the survey. The following generalizations can be made 
from the responses to the grower survey: 

o From a grower's perception/ the irrigation water delivery 
capabilities of water agencies do not appear to be a limiting 
factor to improving management. 

o Growers typically have records of annual crop yield/ water use/ 
and irrigation costs. 

o Some growers reuse tailwater for irrigation but the percent of 
the total applied water is generally less than 5 percent. 

o Very few growers reuse subsurface drainage water. 

o Unlined ditches are used for on-farm water distribution in many 
areas . 

o Most growers think their existing irrigation practices could be 
improved by better management or more efficient irrigation 
systems. 



5- 21 



TABLE 5.6 
SUMMARY OF PRIVATE AND PUBLIC AGENCIES CONTACTED 
TO ASSIST IN THE ON-FARM 
AGRICULTURAL MANAGEMENT ALTERNATIVES GROWER SURVEY 



Agency 



Contact 



Plain View Water District 

Santa Carbona Irrigation District 

West Stanislaus Irrigation District 

Patterson Water District 

Central California Irrigation District 

San Luis Water District 

Panoche Water District 

Broadview Water District 

Westlands Water District 

Tulare Lake Basin Water Storage District 

Lost Hills Water District 

Semitropic Water Storage District 

Buena Vista Water Storage District 

Rosedale-Rio Bravo Water Storage District 

Kern Delta Water District 

Grassland Water District 

Land Preservation Association 

Alliance for Responsible Water Policy 



Mike Azpeitia 
Fred Terrill 
Eugene Carson 
Ron Roos 
Michael Porter 
Cecil Carey 
Dennis Velasco 
Dan Nelson 
Dan Upton 
Brent Graham 
Joe Steele 
Will Boschman 
Martin Milobar 
Mary Collup 
Gilbert Castle 
Dan Marciochi 
Steve Hall 
Jim Tischer 



5-22 



o Some growers need drainage systems but need a method of disposal 
before the system can be installed. 

o The major consideration in following a crop rotation is the crop 
market . 

o Some growers feel they can control their own subsurface drainage 
water but not water from upslope lands. 

o Subsurface drainage is not the result of one grower's operation 
but the total percolating waters from many farms. 

o The following suggestions were provided as ways to reduce 
subsurface drainage volumes or improve drainage water quality. 

Make each grower responsible for his own drainage water. 

Install shallower drainage lines on narrower centers. 

Install tailwater return systems. 

Convert to more efficient irrigation systems. 

Since many growers over irrigate; develop a water management 
system for the water agency. 

Improve surface irrigation systems. 

Implement irrigation scheduling. 

Charge for water lost through excessive irrigation. 

Prevent water users from running excessive tailwater. 

- Use the shallow water table to provide a portion of the crop 
ET. 

Develop technology for on-farm treatment/removal of 
selenium. 

- Provide low- or no-interest loans. 

o The following items are restricting the implementation of on- 
farm management techniques to reduce subsurface drainage flows 
or improve drainage water quality. 

Changes resulting in higher farming costs are unacceptable. 

Crops do not offer sufficient return to pay for improvements. 



5- 23 



The existing technology is too expensive to be supported by 
current commodity values. 

Lack of ability to manage alternative practices. 

Inability to dispose of subsurface drainage water. 

Funding limitations. 

The following institutional and economic conditions limit the 
implementation of on-farm management techniques to reduce 
subsurface drainage flows or improve drainage water quality. 

There are no incentives to improving existing farming 
practices . 

- Depressed farm economy. 

Implementation costs are not recovered by water savings. 

Water costs are not increased for inefficient use/waste. 

High energy costs discourage drip and sprinkler use. 

Change the water delivery date to March 21 to allow growers to 
return excess water to the district for a full refund. 
Without a refund, growers will apply water even if it is not 
needed . 



5- 24 



SECTION 6 
DISCUSSION OF MANAGEMENT ALTERNATIVES 

6.1 POTENTIAL MANAGEMENT ALTERNATIVES 

The list of potential on-farm management alternatives was 
continually updated to reflect additional data obtained through the 
literature review and grower surveys. The development of 
alternative on-farm management plans must include consideration for 
a combination of management alternatives. The selection of 
management alternatives will be based on a grower's financial and 
management capability and the soil and water resources prevalent to 
his farming operation. The potential on-farm management 
alternatives/ which are discussed in greater detail in this section/ 
are summarized as follows. 

1 . Irrigation Water Conservation 

o Improve on-farm water conveyance efficiency. 

o Change to irrigation method appropriate to site. 

o Initiate irrigation scheduling programs. 

o Monitor soil moisture stress. 

o Monitor plant water stress. 

o Utilize weather data to determine evapotranspiration 
demands. 

o Base irrigation timing and amounts on crop water, 
requirements. 

o Reduce off-season irrigation. 



o 



Limit pre-irrigat ion to the amount needed to achieve field 
capacity in the root zone. 



Water Reuse 



o 



Install tailwater and drainage water return facilities, 



o Irrigate with undiluted drainage waters at selected crop 
growth stages. 

o Irrigate with a blend of drainage water and surface or 
well water. 



6- 1 



3 . Crop Management 

o Change planting date. 

o Seed crops in greenhouse and transplant at seedling stage 

o Decrease transpiration losses. 

o Plant different crops/trees. 

o Absorption of soluble selenate by plant roots. 

4. Soil and Subsurface Drainage System Management 

o Manage soils based on mapped soil properties. 

o Field preparation. 

o Reduce evaporation losses. 

o Reduce deep percolation losses. 

o Immobilize selenium in soil or in subsurface drains. 

5. On-Farm Treatment/Storage of Drain Waters 

o Evaporation/storage ponds with special design and 
operating criteria. 

o Immobilize selenium by reduction and/or precipitation of 
selenate in drainage lines or storage ponds. 

o Removal of soluble selenium in treatment/storage ponds by 
bio-accumulation. 

6 . Economic/Institutional/Legal 

o Encourage irrigation districts to increase flexibility 
(frequency, rate, duration) of water delivery at farm 
headgates . 

o Base water allowance (water duty) on crop needs less 
effective rainfall. 

o Establish water pricing to encourage water conservation 
including a sliding scale price related to crop 
evapo transpiration. 

o Establish penalty fees based on tailwater losses and 
drainage water losses. 



6- 2 



o Terminate water supply to growers after the major winter 
rainfall period begins. 

o Withdraw problem lands from production. 

o Install water quality monitoring systems (subsurface 
drainage water, tailwater, storage water ponds, etc.). 

o Develop opportunity for marketing agricultural irrigation 
water to other water users to provide an incentive for 
water conservation. 

6.2 IRRIGATION WATER CONSERVATION 

Water conservation in California is defined by the DWR with respect 
to its impact on the total water supply. Water is conserved if: 1) 
it is not lost by evapotranspiration or to saline water bodies and not 
available for reuse or 2) the usage of a given water supply is 
maximized. Water going to deep percolation or runoff from farms is 
not considered lost if it recharges a usable groundwater basin or is 
reused downstream. 

The difficulty with these concepts is that there is no cost attached 
to the degraded quality of water returned to the groundwater or to 
surface supplies for reuse. If these return waters exceed 
established water quality criteria or further degrade water quality 
such that other users will be faced with costly water treatment, who 
is then responsible to pay for water treatment? Will downstream 
users suffer financially because upstream users are only required to 
meet minimum legal water quality standards? Since water 
degradation is a cumulative process as water is continuously reused, 
is the last user who reduces water quality below legal water quality 
criteria the one who pays for water treatment or should the treatment 
cost be apportioned to all users who contributed in some way to its 
degradation? 

Given these considerations, it becomes imperative to look at water 
conservation not just from the point of view of reducing water losses 
to evaporation and transpiration, and losses to saline bodies of 
water but also from the standpoint of protecting the quality of water 
by reducing return flows of poor quality water to either the 
groundwater aquifer or to surface water supplies. Therefore, the 
intent of this section is to review agricultural water conservation 
measures that will effectively reduce deep percolation and tailwater 
losses of poor quality water to water supplies that may be intended 
for further use. 

Reducing deep percolation and tailwater losses can be approached 
from several different ways at the on-farm level. Initially, 
potential losses may occur in the conveyance of irrigation water from 
the headgate to the point of application. Next, water losses will 
occur during irrigation water application. During irrigation water 

6- 3 



application/ water losses by deep percolation and runoff can be 
minimized by selecting the appropriate irrigation system, by proper 
management of this system, and by proper irrigation scheduling. 
These practices are discussed in this section. 

6.2.1 On-Farm Conveyance System Efficiency 

Conveyance efficiency is defined as the ratio, expressed as a 
percent, of the volume of water delivered to the point of application 
in the field (Wa) divided by the volume of water delivered at the farm 
headgate (Wi ) : 



Ec = 



Wa 
Wi 



100 



[6.1] 



Water losses during conveyance are primarily from seepage, 
evaporation from open water surface, and transpiration from weedy 
vegetation . 

Significant contributions to the shallow groundwater table may 
result from seepage losses from on-farm irrigation water conveyance 
systems, especially from unlined ditches, canals, and regulation 
reservoirs. Evaporation and transpiration losses are considered in 
estimating conveyance system efficiency; however, since they do not 
directly affect seepage losses they are not addressed in this study. 
Therefore, the following discussion covers only seepage losses. 
The amount of seepage from unlined ditches depends primarily on soil 
permeability, water depth in the facility, and depth to water table. 
Soil permeability is affected by water salinity, soil texture, 
exchangeable sodium percentage, and soil cracking. Factors 
affecting water penetration in soils are discussed in detail by 
Biggar et al. (1984). 

Little data are available to evaluate seepage losses from on-farm 
conveyance systems in the San Joaquin Valley, although measuring 
methods are available (Robinson, et al . , 1963; Scott & Houston , 1981; 
and USDA, 1962). Potential water savings from reducing seepage 
losses in the study area cannot be accurately determined from 
existing data. 

Methods to reduce water seepage losses from ditches and canals vary 
from lining ditches with semi-permeable materials to the containment 
of the delivery system in closed pipes (Robinson, et al . 1963; 
Lauritzen & Terrell, 1967; and USER, 1963). Ditches can be lined and 
compacted with fine-textured soil or bentonite (an expanding clay 
material). Techniques for applying bentonite, discussed by Duffin 
(1976), generally require application as a slurry followed by 
settling. Cracking soils or irrigation waters high in soluble 
calcium may reduce the effectiveness of bentonite. The use of 
chemical sealants has also been suggested, but these may have adverse 
environmental consequences since the contamination of soil and water 
resources is a potential problem. 



6- 4 



Several exposed membrane lining materials have been suggested, 
including asphalt-coated jute, butyl rubber sheeting, and 
polyethylene films. Membrane linings may also be buried several 
inches deep to protect against mechanical an'd sunlight damage. The 
recommended lining in this case is a sprayed asphaltic material 
topped by a 6-inch layer of earth (USER, 1963; and Loretzen & Terrell, 
1967). Common hard lining materials include portland cement 
concrete and asphaltic concrete. These linings are much more 
durable than membrane or fine earth lined canals, but may be subject 
to seepage losses (0.1 to 0.2 cubic feet per square foot per day) from 
cracking (Loretzen & Terrell 1967). Further information on design 
requirements for canal or ditch linings is summarized by Kruse et al . 
(1980). 

Regardless of the materials selected, lining of ditches is an 
effective method of reducing seepage losses and effectively 
conserving water for irrigation purposes. 

The selection of a method for lining canals and ditches will depend 
largely on the cost of installation, maintenance requirements, 
degree of seepage, and life expectancy of the material. The overall 
cost of the method should be weighed against costs of recycling 
drainage waters or reclaiming drainage water derived from seepage 
losses. Cost estimates for canal and ditch linings will vary based 
on size of canal, degree of seepage and material used. Price 
fluctuations are not uncommon because many lining and sealant 
materials are petroleum based. Concrete lining is the typical 
approach that has been used in the study area. 

The most effective method of reducing seepage losses from irrigation 
water delivery systems is by using pipelines. However, in some 
areas where distribution ditches are also used for tailwater 
recovery/reuse purposes, the installation of pipelines may not be 
practical. With closed pipes, losses can be reduced to near zero. 
Recent introductions of more cost effective pipe materials have made 
this management alternative more viable. Selection of the pipeline 
system will depend on many design factors, including whether the pipe 
is to be buried, operating pressures, and required capacity. Low 
pressure pipe systems which are used as delivery mechanisms for many 
surface irrigation systems are discussed by Kruse et al. (1980) and 
Robinson et al . (1963). Preferably, surface systems use aluminum 
pipe, although plastic (PVC) and flexible rubber tubing are also 
used. For buried systems, the use of plastic pipe (PVC, ABS, PE) is 
common since it is less expensive and easier to install than 
traditional concrete materials. For more detailed information on 
the design, operation, and maintenance of low pressure pipeline 
delivery systems, refer to Kruse, et al. (1980). 



6- 5 



The use of sprinkler irrigation systems generally requires the use of 
high-pressure pipelines. Seepage losses can be minimized by proper 
maintenance of connectors. High-pressured delivery systems are 
generally discussed in context with sprinkler irrigation systems in 
total (Addink et al., 1980 and Pair, et al. 1983). 

The use of pipeline systems almost entirely eliminates water losses 
from the conveyance system. Subsurface drainage is positively 
impacted as a result of the reduced water losses. 

Unlined canals are typically used for on-farm water distribution 
purposes in the study area. This approach is the most economical 
when compared to the other alternatives but also results in the 
greatest seepage losses. Without some incentive, growers in the 
project area will probably continue to use unlined ditches. 
However, if irrigation systems requiring pressure are installed 
(sprinkler or trickle), pipeline transmission systems will probably 
be required. To date, most growers in the study area have not seen 
the need to improve on-farm conveyance system efficiency. 

6.2.2 Irrigation Efficiency 

Irrigation efficiency is a function of irrigation system management. 
Therefore, a state-of-the-art irrigation system will only be as 
efficient as management allows. To provide acceptable irrigation 
system management, steps must be taken to: 1) increase the 
uniformity with which irrigation water is applied; 2) provide the 
required amount of irrigation at the proper application rate; 3) 
minimize water losses from evaporation, deep percolation, and 
runoff; 4) reduce the amount of pre-irrigation ; and 5) schedule 
irrigation frequency. 

Irrigation efficiency at the farm level generally implies either 
maximizing the use of an available water supply or using a minimum 
amount of water to achieve a desired production level. The 
contribution of contaminants from source areas is a concern. 
Improving irrigation efficiency will help to manage the amount of 
those elements entering the subsurface drainage water disposal 
system. 

Irrigation efficiencies may have different meanings depending on the 
type of management unit (hydrologic basin, county, irrigation 
district, farm, or field) and on the period for which it is defined 
(calendar year, growing season, or irrigation event). In this 
report, irrigation efficiency is defined with respect to the farm 
management unit for the calendar year. The selection of the 
calendar year is based on the fact that drainage problems are 
continuous and cumulative and may be a problem at any time of the 
year. Irrigation efficiency (Ei) is then defined as the ratio 
expressed as a percent of the evapotranspiration requirement of a 
crop (ET) less effective precipitation (Re) divided by the amount of 
water delivered to the farm headgate (Wi): 



6- 6 



Ei = 



ET - Re 
Wi 



[6.2] 



The irrigation efficiency of the farm can be separated into two 
components, conveyance efficiency (Ec) and irrigation application 
efficiency (Ea ) . 

The irrigation application efficiency (Ea) is defined as the ratio 
expressed as a percent of the ET less Re divided by Wa : 



Ea = 



ET - Re 
Wa 



[6.3] 



The overall irrigation efficiency (Ei) is simply the product of the 
conveyance efficiency and the application efficiency: 

Ei = Ec X Ea [6.4] 

Leaching requirement (LR) is defined as the fraction of irrigation 
water required in excess of crop water requirements to maintain a 
salt balance in the soil profile (Jensen et al. 1957). This term is 
added to the numerator of equation 6.3. Including LR in the equation 
results in a higher perceived irrigation efficiency. However/ deep 
percolation losses due to the difference between ET and applied water 
are the same. Because of this, LR is not considered as part of the 
definition of Ei. 

Another definition of irrigation efficiency adds the precipitation 
term to the denominator rather than the numerator. In this case the 
equation defines overall water use efficiency rather than irrigation 
efficiency. For further discussion of the terminology of 
irrigation efficiency, refer to Jensen et al . (1967). 

An efficient irrigation system requires an accurate application of 
irrigation water at the proper flow rate. This requirement 
necessitates that on-farm conveyance facilities have adequate water 
control structures and that accurate water measurement methods are 
used. The effort to accurately determine crop water requirements is 
meaningless unless an accurate method to control and measure flow 
rate and volume is provided. 

Irrigation Water Control 

Control over the quantity of water delivered to a field and the rate 
of delivery is the first step to improving overall irrigation 
application efficiency. Several measures can be taken to overcome 
fluctuations in the flow rate of open ditch irrigation delivery 
systems so that optimum stream flow rates can be achieved (Criddle et 
al. 1956). The use of automated control devices is also possible, 
especially where water is delivered to the farm under pressure in 
closed pipelines. This allows more precise control of run time 



6- 7 



(Hart et al. 1980). Further information on the control and 
measurement of irrigation water delivery systems can be found in 
Withers and Vipond, Chapt. 6 (1980), Kruse et al. (1980), Robinson et 
al. (1963), Griddle et al. (1956), Scott and Houston (1981), and 
Merriam and Webster (1978). 

Water control structures can be distinguished between those required 
for open channel devices and closed systems (pipes). The selection 
of an appropriate control system depends primarily on the type of 
conveyance and irrigation system used. Although a water control 
structure may serve several purposes, such as energy dissipation, 
water diversion, and trash removal, interest is directed toward 
regulating deliveries to fields. Water levels are normally 
maintained by either portable or permanent check, devices. Some 
check structures also double as water measuring devices. Various 
check structures are reviewed by Robinson et al. (1963), Robinson and 
Humphreys (1967), and Kruse et al . (1980). Discharge control 
devices include turnouts, siphons, and diversion boxes. These 
devices which may be used in conjunction with water level control 
devices are described by Robinson and Humphreys (1967) and Kruse et 
al. (1980). Costs of acquiring and maintaining these discharge 
control devices are relatively low; however, these are manual 
systems and therefore require a significant labor and maintenance 
commitment. If properly used and maintained, these devices can 
effectively control and direct water. 

To improve the control of water distribution timing and flow rates in 
conveyance systems with a savings in labor, water, and energy, 
increasing use is being made of automated or semi-automated control 
structures. Dedrick (1978) describes a semi-automated system for 
gate control in level basin irrigation systems. Other devices are 
noted by Robinson and Humphreys (1957) and Kruse (1980). 

Where water is distributed by closed or semi-closed pipeline to 
surface irrigated fields, low pressure systems are generally 
employed. Gates and valves for discharge control are described by 
Robinson et al . (1963) and Robinson and Humphreys (1967). 

- Automated Control Devices 

The use of automated control devices is more easily adapted to closed 
pipe conveyance systems, but flow rates may be affected by line 
pressure fluctuations. Structures to moderate line pressure 
changes such as stand pipes and automated turnout valves are 
discussed by Kruse et al . (1980). 

Two recent advances in automated control techniques for water 
deliveries in surface irrigation systems are the surge flow method 
and the cablegation method. Both systems have the advantage of low 
labor requirements compared to traditional methods of siphoning or 
manually controlling pipe gates. These methods are not widely used 
in the study area because the technology has only recently become 



6- 8 



available. Both systems appear well suited to the existing crops 
and soil conditions in the study area. However, more field testing 
is needed to determine their utility. 

Surge Flow System 

In the surge flow system (Bishop et al . , 1981), water is delivered to 
furrows intermittently. It was shown that this method 
approximately doubled the advance rate of water over the field 
compared to the same amount of water continuously applied. This 
allows for a more uniform distribution of applied water. 

The design criteria for this system simply require that water 
delivered under constant pressure be alternatively diverted from one 
half of a gated pipe to the other half by a butterfly valve or a surge 
flow valve at pre-selected times. The costs of implementing this 
type system can be relatively low if a closed pipe conveyance system 
already exists. Conversion to this type of system requires gated 
pipe, a surge flow valve and a hydrant adaptable to a riser. Many 
systems provide the option of surging to accelerate water flow or 
cutback to minimize tailwater, resulting in more effective coverage. 

Cablegation System 

The cablegation system, developed by Kemper and Heineman (1981), 
delivers water from a gated pipe within which a polyethylene plug 
connected to a cable in the pipe is automatically unreeled in the 
direction of water flow. The pressure of the water against the plug 
moves it along and water is forced out of the pipe in back of the plug. 
The rate of discharge at each gate decreases as the plug moves further 
along down the pipe. The system is essentially an automated 
traveling gate device. Care must be taken so that the maximum 
discharge rate is non-erosive. Very little water is lost by leakage 
from the system. 

- Irrigation Water Measurement 

Water measuring devices can either be incorporated in water delivery 
systems as part of the control structure or can be temporary 
structures for irrigation evaluations. Knowledge of the rate of 
water delivery to the field is a prerequisite to achieving optimum 
irrigation application efficiency. The accuracy of measuring 
devices, however, may still be no better than approximately 5 to 10 
percent (Robinson and Humphreys, 1967). 

- Open Channel Water Measurement 

Open channel measuring devices include a variety of weirs, flumes, 
floats, current meters, vanes, orifices, and control gates. Flumes 
require less water drop than weirs, which is advantageous in the 
level terrain of the San Joaquin Valley. Two commonly used classes 

6- 9 



of flumes are Parshall flumes and long throated flumes (Replogle and 
BoS/ 1982). The ease of use and transportability of the Parshall 
flume makes it extremely valuable for flow measurements in field 
ditches. Several devices used to measure water flows in closed 
pipeline systems are in-line water meters (propeller or disk type) 
and pitot tubes which measure the water pressure on small orifices in 
a small tube inserted crosswise in the pipeline. The simplest 
technique suitable for evaluation of small irrigation streams is to 
determine the time required to fill a container of known volume from 
the stream discharge. For more information on measuring devices 
refer to Robinson et al. (1963); Robinson and Humphreys (1967), and 
Scott and Houston (1981). 



- Excessive Irrigation Applications 

In the western San Joaquin Valley, irrigation management has 
generally resulted in over-irrigation. In many areas this has 
caused soil waterlogging which has been relieved with the 
installation of tile drains and/or the application of soil 
amendments such as gypsum. Soil physical and chemical properties 
and their effects on irrigation and drainability are discussed 
Sect ion 6.5. 



in 



Non-uniform water distribution that causes over-irrigation can 
result in waterlogging of soils with low permeability. The 
saturated soil environment subsequently reduces crop yields. 
Additionally, excess deep percolation losses may cause a perched 
water table to develop above a very slowly permeable soil layer. 
Salts in the soil profile may also be elevated into the root zone by 
the rising water table. Conversely, in areas of the field that are 
under-irrigated, crops may suffer from a soil moisture deficit 
before the next irrigation cycle. Losses of applied fertilizers and 
amendments are also directly related to over-irrigation. 
Inefficient upslope irrigators are contributing subsurface drainage 
water flows to the perched water table in the valley basin area. The 
contribution may approach the volume lost as a result of their 
inefficient irrigation. 

A measure of how completely water is stored in the root zone during an 
irrigation is determined as follows: 



Es 



100 



(Ws) 
Wn 



[6.5] 



Where Es = water storage efficiency, Ws = water stored in the root 
zone during an irrigation event, and Wn = water needed in the root 
zone prior to the irrigation. 

In order to determine the potential for improving irrigation 
application efficiencies, quantities of irrigation water applied 
and lost by deep percolation, evapotranspiration , and runoff as well 
as the water application need to be measured. Specific techniques 



6- 10 



for measuring and evaluating these parameters are given by Merriam 
and Keller (1978) and Griddle et al . (1956). 

- Application Uniformity of Surface Systems 

The uniformity of water distribution in surface irrigation systems 
is significantly affected by the topography of the field and soil 
properties. Uneven topography can lead to water runoff from 
elevated areas and water ponding in low areas. With current land 
leveling technology/ topographical effects should be minimal. Land 
leveling is of primary importance when installing surface irrigation 
systems. A properly leveled and graded field will permit a more 
uniform distribution of irrigation water flowing from the head gate, 
ditch, or gated pipe. With the introduction of laser leveling, very 
precise leveling can be achieved (+ .05 ft.). For further 
discussion refer to Jensen, 1957, p. 1139; Dedrick. et al. (1978); 
Anderson et al . (1980); Daubert and Ayer (1982); and USDA (1970 and 
1979). 

Soil factors affecting distribution uniformity include soil 
infiltration rates which are influenced by chemical, textural, and 
structural variations; soil compaction; and soil moisture holding 
capacity. A field with highly variable soil properties has inherent 
inefficiencies that may be difficult to overcome by even the best 
managed surface irrigation system. 

Application uniformity can be improved by modifying intake 
opportunity time over the length and breadth of the field being 
irrigated. The intake opportunity time (or contact time) is the 
time water on the soil surface has an opportunity to infiltrate into 
the soil. It is calculated as the difference between the advance 
time and recession time of applied irrigation water (Figure 6.1). 
The advance time is the time after irrigation initiation that it 
takes for an irrigation run to advance a specified distance down a 
border strip or furrow. The recession time is the time after 
initiation of the irrigation run when the water finally recedes or 
infiltrates into the soil at a specified distance from the point of 
irrigation. The intake opportunity time changes with the distance 
from the point of irrigation inflow. Where runoff is allowed, 
intake opportunity times are generally greatest at the head of a 
furrow and least at the tail of the furrow. Because of this, the 
irrigation run is allowed to continue long enough so that the 
opportunity time at the end of the furrow is sufficient to make up the 
moisture deficit in this portion of the field. These design 
criteria mean that a certain portion of irrigation water will 
contribute to deep percolation losses, primarily toward the head of 
the furrow. 

The irrigation application efficiency can be estimated by 
determining the advance ratio ( AR ) , which is the ratio of the advance 
time to the end of the furrow to the duration of irrigation. Advance 
ratios of 1:3 or 1:4 have been suggested as adequate by Merriam and 



6- 11 



r' 




End of furrow 



Deep percolatio 



THEORETICAL ADVANCE AND RECESSION CURVES 

PLOTTED ABOVE THE RESULTING WATER DISPERSION CURVES 

FOR DIFFERENT FURROW ADVANCE RATIOS 



Reference: Adapted from Merriam and Keller, 1978 
AR Advance Ratio 
SMD - Soil Moisture Deficit 



ScKjte Enolneertnci Corp)CDraac3n 



FIGURE 6 



J 



6-12 



Keller (1978) (Table 6.1). Where the advance ratio is too high 
measures can be taken to reduce this ratio. However, the benefits of 
reducing deep percolation must be considered in relation to the 
potential crop yield loss from inadequate irrigation at the end of 
the run. The effect of advance ratio on water distribution under 
furrow irrigation is illustrated in Figure 6.2. Another method of 
calculating the water intake percent that is lost to deep percolation 
is summarized by Bishop et al . (1967). 

TABLE 6.1 
THEORETICAL WATER DISPERSION, DISTRIBUTION, AND 
UNIFORMITY PERCENTAGE FOR VARIOUS FURROW ADVANCE RATIOSl/ 



Item 



Advance Ratio 
Without return flow 



1:4 



1:2 



1:1 



Advance Ratio 
With return flow 



1:4 



1:2 



1:1 



Applied water 

Portion infiltrated 

Portion stored 

Deep percolation loss 

Runoff loss 

Distribution uniformity 



100% 100% 100% 

68 80 93 

61 68 70 

7 12 23 

32 20 7 

91 85 75 



100% 100% 100% 

91 85 75 

9 15 25 ■ 



91 85 75 



!_/ Adapted from Merriam and Keller, 1978. 

2_/ Advance Ratio is the ratio of water advance time to the end of the 
furrow to the duration of irrigation. 



Several measures can be performed to improve irrigation distribution 
uniformity. Where soils have highly variable infiltration rates, 
field boundaries should approximate boundaries between different 
soil types where practical. Length of irrigation run, field slope, 
water flows, and furrow sizes should be designed based on soil 
characteristics to maximize uniformity. 

Shortening the length of irrigation runs by dividing a field may 
result in a significant improvement in irrigation efficiency, 
especially if the soil has a high infiltration rate. The effect of 
reducing the length of an irrigation run on advance time, intake 
opportunity time, depth of water applied, and deep percolation is 



6- 13 




(SaiONIH) 3tNU 

ADVANCE AND RECESSION CURVES FOR BORDER-STRIP IRRIGATION 



Reference: Adapted from California DVVR Bulletin 198-84, 1981. 
BoijB Encjt-tBorlrKj Cotxxsraaon -^ FIGURE 6.2 

6-14 



illustrated in Figure 6.3. This technique will require additional 
capital expenditures for the construction of more distribution and 
tailwater recovery systems. Additional costs will result from 
increased field operations and labor requirements. 

Advance time can also be reduced by decreasing furrow width or by 
irrigating every other furrow, given the same overall field 
application rate. This method may not be effective if the soil is 
highly erosive or the irrigation event is at a time when crop 
consumptive use of water is at its greatest. In the latter case, an 
insufficient percentage of the soil may be exposed to irrigation 
water to allow an adequate rate of intake if the soil is slowly 
permeable. Cracking soils such as those found in the study area also 
reduce the efficiency of this approach. 

Through traditional methods of furrow and border strip irrigation, 
the amounts of water needed for adequate intake opportunity time at 
the end of the furrow may contribute to drainage water flows. This 
may result from direct discharge of tailwaters into open drain 
structures or indirectly from deep percolation of ponded tailwater. 
Tailwater losses most commonly occur from furrow irrigated and 
border-strip irrigated fields which comprised about 82 percent of 
the acreage under irrigation in the San Joaquin Valley in 1980 (DWR, 
1983). 

There are several additional advantages that occur as a result of 
recycling tailwater. Dissolved fertilizer and pesticides are 
returned to the field. Since tailwaters are typically much lower in 
salinity and boron than subsurface drainage water, the reuse 
presents a lower salinity hazard than recycling subsurface drainage 
waters . 

Other measures that can be used to increase irrigation efficiency and 
to reduce tailwater losses include: 1) changing the irrigation 
system to a level-basin operation where all waters are confined to a 
level field or 2) cutting back the rate of stream flow as irrigation 
water approaches the end of the field. In the latter case, automatic 
control devices such as the previously discussed surge-flow or 
cablegation systems can be used to cut back irrigation flows. 
Level-basin irrigation systems are discussed in Section 6.2.4. 

Application Uniformity of Sprinkler and Drip Systems 

Sprinkler irrigation is an effective method of increasing irrigation 
efficiency and provides a greater degree of control over water 
application rates than surface irrigation. Sprinkler irrigation 
systems can be operated efficiently over a wider range of topographic 
and soil infiltration characteristics. These advantages, however, 
can only be realized through proper system design, operation, and 
management . 

With proper sprinkler irrigation system management, many of the 



6- 15 



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xTTTTTTv\r^:\V^^^ 


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1300 2600 

DISTANCE ALONG FIELD (FEET) 




1300 2600 

DISTANCE ALONG FIELD (FEET) 



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DISTANCE ALONG FIELD (FEET) 



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DISTANCE ALONG FIELD (FEET) 




LU 6 




^SSSSS^^ ^S^SSSs:^ 



^OEEP PERCOLATION -i 
LOSSES 



EFFECT OF REDUCING THE LENGTH OF FURROW 



Reference: Adapted from California DWR Bulletin 198-84 1984. 



Bcxjte ErKjmeenno CortDoraOcn 



FIGURE 6.3 



6-16 



problems inherent to flood irrigation; such as deep percolation 
losses/ can be minimized and tailwater losses can be eliminated. 
Significant increases in irrigation efficiencies can also be 
realized. Merriam and Keller (1978) indicate that the potential 
application efficiency for sprinkler irrigation systems is 65-85 
percent • 

Disadvantages of sprinkler irrigation systems are primarily related 
to higher capital, operational, and maintenance costs. The solid 
set sprinkler irrigation systems have the highest capital costs. 
Where hand-move sprinkler systems are involved, labor costs are 
usually high. With the high costs associated with sprinkler 
irrigation systems, it is imperative to have an efficiently managed 
system. 

Sprinkler systems can also be inefficient if designed or operated 
improperly. Potential water losses to the shallow groundwater 
table may result from leakages in the distribution system, water 
applications beyond the crop water requirement, and runoff. 
Evaporation losses during irrigation may range from 5 to 15% 
(Merriam, 1977); however, these losses do not directly impact the 
shallow water table. Leakage losses can generally be reduced by 
proper system maintenance. Runoff can normally be avoided by 
reducing irrigation application rates below the soil infiltration 
rate . 

The greatest potential loss to deep percolation results from poor 
distribution uniformity. These losses result from system design 
factors such as nozzle size and spray characteristics, variable 
water pressure, and nozzle and line spacing. To assure adequate 
irrigation over the whole field, water in excess of the average soil 
moisture deficit may be required to provide sufficient irrigation to 
those areas of a field receiving the least water. 

Measurement techniques to determine irrigation water requirement 
and distribution uniformity are summarized by Merriam and Keller 
(1978). The distribution uniformity (DU) is the ratio of the 
average low quarter depth of water infiltrated divided by the field 
average. The low quarter is that quarter of the field with the 
lowest average depth of water infiltrated. 

One of the most common methods of determining the uniformity of 
sprinkler application was developed by Christiansen (1942). The 
coefficient of uniformity ( CU ) is calculated as follows: 



CU = 100 (1.0 - 



X) 



[6.6] 



MN 



where X is the total applied water for the individual observations, M 
is the average depth of applied water, and N is the number of 
observations. Theoretically, the absolute uniformity by this 
method is 100% although a uniformity above 80% is considered very 



6- 17 



good. Several other measures of uniformity are discussed by 
Christiansen and David (1967). The water distribution pattern can 
be graphically represented by the cumulative frequency diagram 
(Figure 6.4) where percent of average depth of irrigation needed is 
plotted against the percent of area irrigated (Jensen et al., 1967). 
The effect of sprinkler irrigation distribution and amount on 
irrigation and water storage efficiency is shown in Figure 6.5. 

Merriam (1977) discusses several measures for improving 
distribution uniformity of sprinkler irrigation systems. Poor 
water distribution by individual sprinklers can be partially 
alleviated by increasing sprinkler overlap or decreasing lateral 
move distances of hand-move or other periodic move systems. For a 
single line system; the use of alternate sets is suggested. In this 
practice during alternate irrigation the lateral is placed midway 
between the placement of the laterals during the previous 
irrigation. Adjustment of the duration of the set and line pressure 
must be considered when adjusting spacings. 

Where the distribution pattern is distorted by wind, using lower 
pressure systems (large droplet size), closer spacings, and avoiding 
windy periods are alternatives to improving distribution 
uniformity. Poor distribution uniformity caused by pressure 
differences in the system can be reduced by using flow regulation 
devices, larger pipe diameters, and better alignment of the lateral 
with respect to the ground slope. 

Drip irrigation systems overcome many of the potential 
inefficiencies related to drift, wind, evaporation, etc. with 
efficiencies as high as 85 to 90% achievable. Drip irrigation, 
although tested on a number of crops, is not adapted to all crops in 
the study area. Further, positive economic returns from this 
approach have not been widely demonstrated because revenue generated 
as a result of increased crop yield generally does not offset the cost 
of installing and operating the system. 

6.2.3 Irrigation Scheduling 

Irrigation scheduling is the management practice of determining how 
much water to apply during an irrigation and the timing of the 
application. Although simply stated, proper irrigation scheduling 
is not easily achieved. The purpose of irrigation scheduling is to 
maximize crop production per unit of applied water. In the context 
of this report, the purpose of irrigation scheduling is to maximize 
irrigation efficiency (and reduce deep percolation) while 
maximizing crop production. 

Irrigation scheduling requires a knowledge of the total crop water 
requirement for the particular growing condition. The applied 
irrigation water requirement is considered the quantity of water 
required for growing a crop considering other factors and system 
inefficiencies. It depends on actual crop evapotranspirat ion , the 



6- 18 



160 



140 



S 120 

Q 
UJ 
UJ 



f 100 



AMOUNT NEEDED TO ADEQUATELY 
IRRIGATE 90% OF THE AREA 




'^^-^7^^??%^^^ LEACHING REQUIREMENT^ 



y 



^80 
cc 

UJ 



60 - 



UJ 

o 
a. 



DISTRIBUTION PATTERN 



DISTRIBUTION COEFFICIENT 
FOR 90% OF AREA 



40 60 

PER CENT OF AREA 



80 



100 



ILLUSTRATION USING THE DISTRIBUTION PATTERN IN EVALUATING 

IRRIGATION ADEQUACY AND ADJUSTING THE AMOUNT OF WATER 

APPLIED TO OBTAIN THE DESIRED ADEQUACY 



Reference: Adapted from Jensen et al., 1967. 



Goufe Enainsenncj CorcDoraOon 



FIGURE 6.4 



6-19 




Eq - I007o 



Es=507o 



75 7o 




Eo = 90% 



Es= 907o 



Cu=857o 




Es=l007o Cij=9 57o 



TYPICAL EFFECTS OF WATER DISTRIBUTION PATTERNS 
ON A CROP UNDER SPRINKLER IRRIGATION ASSUMING NO RUNOFF 

E = Irrigation Application Efficiency 
Eg= Water Storage Efficiency 
C = Coefficient of Uniformity 



Reference: Adapted from Hansen, 1960. 
Soijte EncjIneGrlnci CorfDor^acDn ———^-^^ 



FIGURE 6.5 



6-20 



cropping pattern, type of planting (density or spacing), leaching 
requirement, irrigation management, and effective precipitation. 
For discussion of factors affecting the crop water requirement, 
refer to Pruitt (1972), Doorenbos & Pruitt (1977), and Burman et al . 
(1980). 

Evapotranspiration (ET), which is generally considered synonymous 
with consumptive use ( CU ) , is the quantity of water transpired by 
plants, retained in the plant tissue, and evaporated from adjacent 
soil surfaces in a specified time interval (California DWR, 1975). 
Daily ET increases during the growing season as the crop matures and 
decreases with crop senescence at the end of the growing season. 
Figure 6.6 illustrates the change in cotton ET during the growing 
season . 

Two basic methods are employed to directly measure evapotrans- 
piration. One involves the measurement of changes in soil moisture 
content in the crop root zone over time, either gravimetr ically or 
non-gravimetrically , i. e. neutron probe. Soil moisture measuring 
techniques are discussed in detail by Gardner (1965) and Holmes et 
al. (1967). The problem with these techniques is that water losses 
by deep percolation are difficult to determine. The second and more 
accurate technique is lysimetry, in which a volume of soil is 
isolated hydrologically from its surroundings either in the field or 
in a laboratory setting. Precise measurements can then be made of 
changes in soil water content by either weighing the lysimeter 
directly or measuring soil moisture indirectly. For further 
discussion of methods used to directly measure plant ET , refer to 
Tanner (1967); Jensen (1973); and Doorenbos and Pruitt, 1977). 
Measured monthly ET values for various crops grown in California are 
summarized in California DWR Bulletin 113-3 (1975). 

Since measured monthly ET values are costly to determine, they have 
been correlated with other more easily measurable climatic data. 
This approach allows the estimation of crop ET from climatic data 
alone. Climatic data may include measurements of solar radiation, 
humidity, temperature, wind, sunshine, evaporation, etc. Several 
empirical formulae have been developed to predict crop ET based on 
using one or more of these climatic factors (Tanner, 1967; Doorenbos 
and Pruitt, 1977; and Burman et al . , 1980). In California, pan 
evaporation (EPan) measurements have been used as a basis for 
determining crop ET (California DWR, 1975). This approach is based 
on the low variability in potential ET measurements during the 
primary growing season in California (Pruitt, as cited by Tanner, 
1967). The estimated monthly crop ET is determined by multiplying 
the pan evaporation for the area by monthly ET/EPan ratios for the 
specific crop. Values of ET/EPan for major crops grown in 
California are summarized in California DWR Bulletin 113-3 (1975). 

Although irrigation scheduling has a great potential for improving 
irrigation efficiencies, it has not been widely accepted in 
California because of grower resistance and cost (Liss et al. 1980). 



6- 21 



r 



I 
u 

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UJ 
V) 

3 

cc 

LU 

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APRIL I 



MAY 



60 80 100 120 140 

DAYS AFTER PLANTING 
JUNE I JULY I AUGUST | SEPT. | OCTOBER 



200 



CUMULATIVE WATER USE (EVAPOTRANSPI RATION) , DAILY WATER 
REQUIREMENT, AND MONTHLY WATER USE FOR COTTON 



Reference: From studies at the USDA Cotton Research Station and 
UC West Side Field Station. 



ScKjte Ena/neert-Kj CorccDraaon 



FIGURE 6.6 



6-22 



with recent simpler, more cost effective techniques for determining 
soil moisture contents and plant stress, as well as improved water 
budget methods, acceptance of this technology may become more 
widespread. However, the cost of irrigation water in the San 
Joaquin valley is relatively low compared to the total production 
cost. Further, adequate financial incentives may not exist under 
present conditions to repay the cost of irrigation scheduling at the 
farm level. Wider acceptance of this approach will depend on 
proving its cost effectiveness by demonstrating higher crop yields 
or the reduction of water costs and irrigation labor costs that 
result from fewer irrigation events required over the growing 
season . 

A further constraint to proper irrigation scheduling is the 
availability of water for irrigation on demand. The delivery system 
must be sufficiently flexible to provide irrigation water to the farm 
headgate at the proper frequency, rate (or pressure), and duration to 
match the needs of the irrigation schedule for the crop (Merriam, 
1974; and Replogle and Merriam, 1980). The problem of maintaining 
uniform delivery flow rates was noted by Clemmons (1983) where the 
average coefficient of variation (CV) for delivery flow rates ranged 
from roughly 0.4 to 0.3 for an irrigation district canal system in 
Arizona. A study of water district flexibility in California 
pointed out that the major limitations to delivering irrigation 
water to the headgate on demand was due to the advance notice 
requirement of major water suppliers such as the U.S. Bureau of 
Reclamation and the Department of Water Resources to make changes in 
flow rates to water districts (JM Lord, Inc., 1982). 

Several methods are used for determining the time when a crop 
requires water. These include the calendar method, soil moisture 
status, plant stress indicators, and the water budget method. All 
of these methods are used to some extent by growers in the study area. 
These methods are reviewed by Haise and Hagan (1967) and California 
DWR (1984). 

Calendar Method 

The least efficient method of determining when a crop requires water 
is the calendar method, where irrigation events depend on the water 
delivery schedule of the irrigation district. The irrigation 
system may also be designed such that irrigations are applied using 
some pre-determined schedule. The frequency of delivery may be 
fixed such that the only control is on the quantity of water applied 
for the irrigation event. For annual crops, the first irrigation, 
when plant root development is minimal, is likely to be very 
inefficient. During the peak of the growing season, moisture 
depletion in the root zone may occur before water is available, thus 
potentially reducing yields. The farm manager may have few options 
to improve irrigation efficiencies with the calendar method, short 
of reducing crop yields. 



6- 23 



Soil Moisture Status 

Irrigation applications are scheduled when the soil moisture content 
of the root zone falls below a prescribed percentage or tension. 
Since soil moisture measurements are generally not read on a 
continuous basis/ moisture measurements should be plotted as a 
function of time such that soil moisture can be extrapolated to the 
point in time when irrigation is required (Campbell and Campbell/ 
1982). Soil moisture status can be determined by the feel method; by 
gravimetric analysis/ and indirectly by a neutron probe meter or time 
domain ref lectometry (TDR). The neutron probe (Holmes et al . / 1967; 
and Gear et al . / 1977) has the advantage of being able to rapidly 
determine soil moisture status in the field. The method involves 
the placement of a neutron radiation source in an access tube in the 
field and measuring neutrons with a detector that is shielded from 
the radiation source. Since the neutrons are scattered by hydrogen 
nuclei/ the neutron count by the detector is proportional to the soil 
moisture content. Soil moisture contents for each access tube site 
are calibrated initially to the neutron count for more accuracy. 
The high cost of the neutron probe generally restricts the use of this 
device to qualified commercial irrigation schedulers. The TDR 
system is primarily a research tool at this time but may prove to be a 
rapid and safe technique for determining both soil moisture content 
and soil salinity in one measurement (Dalton et al./ 1985; and 
Dasberg and Dalton, 1985). 

Methods for calculating soil moisture tension are especially useful 
in determining when to irrigate since they are highly correlated with 
plant response. Useful devices include tensiometers and electrical 
resistance blocks. Tensiometers are essentially closed tubes with 
a porous ceramic cup at one end that allows the movement of water but 
not air unless the soil moisture tension exceeds about 100 centibars. 
Tensiometers are placed in the soil/ ceramic cup end down/ to the 
depth at which the soil moisture status is to be determined. To the 
upper end is attached a mechanical pressure gauge or a rubber septum. 
Tensiometers are discussed in more detail by Marsh (1972). With a 
rubber septum/ tension can be measured with a pressure transducer 
(Marthaler et al . / 1983). Soil moisture tension can also be 
determined by using gypsum moisture blocks that are buried in the 
soil. The resistance across the moisture block/ measured by passing 
a current through the block via two wires connected to the block and 
an outside current source, is proportional to the soil moisture 
content. Soil moisture measurement techniques are discussed in 
more detail by Holmes et al. (1967); and Haise and Hagan (1957). 

Guidelines for determining when to irrigate based on soil moisture 
tension are summarized by Taylor (1965) and Hagan and Stewart (1972) 
for different crops. These guidelines/ however, may not be adequate 
for trickle irrigation systems (Wierenga and Sadiq, 1985). 

New advances in soil moisture monitoring may allow remote data 
accumulation by computer. As a further advance/ irrigation systems 



6- 24 



are being designed to automatically irrigate when soil moisture 
tension reaches a certain critical level. An automatic irrigation 
control system in which soil moisture is monitored by a soil matrix 
potential sensor was described by Zazueta et al. (1985) and Phene et 
al. (1981). The researchers were able to schedule irrigations 
delivered by a subsurface drip system to processing tomatoes so that 
losses of water by deep percolation were minimized. This approach 
is primarily adapted to automated sprinkler or drip irrigation 
systems. 

General considerations for scheduling irrigations based on soil 
moisture are discussed by Haise and Hagan (1967) and Campbell and 
Campbell (1982). These include considerations for the spatial 
variability of field soil water properties, the crop and its 
associated root system, the flexibility of the water delivery 
system, and the cost and ease of using soil moisture measuring 
techniques • 

Plant Stress Indicators 

Several observational methods can be used to determine plant stress 
including changes in plant color or wilting. Generally, when plant 
stress is observed, irrigation will be too late to prevent some 
supression of plant growth and yield. More recent techniques that 
are proving highly valuable are the measurement of leaf water 
potential using a pressure chamber technique (Grimes and Yamada, 
1982) or the measurement of plant temperature with an infrared 
thermometer (Pinter and Reginato, 1981; and Hatfield, 1981). 

Water Budget Methods 

These methods do not rely on soil or crop measurements but on the 
calculation of crop evapotranspiration from known climatic data 
using one of several empirical equations or models. These methods 
are commonly used by irrigation scheduling services but must be 
calibrated against soil moisture contents to allow for variations 
caused by soil properties, cultural practices, irrigation methods, 
and variations in irrigation application rates and uniformities. 

Another critical factor to consider in scheduling irrigations is the 
quantity or depth of water to apply. This requires taking soil 
samples from the field and determining their soil moisture 
characteristic curves, i.e., the relationship of soil moisture 
tension to soil moisture content. From this information the 
quantity of moisture that a soil can retain can be determined as well 
as the quantity remaining in the soil at the crop permanent wilting 
percentage. The difference in these water quantities, the 
available moisture content, is determined for several increments of 
soil depth to the extent of the maximum root zone depth of the crop. 
Normally, only a certain percentage moisture depletion is allowed 
for each increment to address variations in irrigation uniformity 
and root penetration. 

6- 25 



6.2.4 Irrigation Methodology/Technology 

In 1980/ approximately 82 percent of all irrigated acreage in the San 
Joaquin Valley was irrigated by gravity flow systems. Furrow and 
border systems accounted for 48 percent and 34 percent of the total 
acreage under irrigation respectively. Sprinkler systems comprised 
about 14 percent of the remaining irrigated acreage with hand move 
systems being the most common. Only about 2.4 percent of the 
irrigated acreage was drip irrigated with less than 1 percent under 
subsurface irrigation. Most of the subsurface irrigated acreage is 
in the Delta area (California DWR, 1983). 

The type and design of irrigation system used is determined primarily 
by economics. Soil physical properties/ topography of the land/ the 
crop grown/ and cultural practices are other considerations (Table 
6.2). The relatively flat floor of the San Joaquin Valley lends 
itself well to surface or gravity irrigation systems/ especially 
with recent laser leveling technology. The irrigation system 
itself is not inherently efficient or inefficient in its water 
application. The selection of the proper irrigation system for the 
crop grown/ soil physical properties/ and water delivery system 
should result in a potentially efficient system. The cost 
considerations of installing/ maintaining/ and operating a system/ 
however/ may result in a cheaper but more inefficient system. 
Likewise/ an irrigation system appropriate for one cropping practice 
may not be the best for another if market conditions require a change 
in crops grown. The cost of changing or modifying the existing 
system may be prohibitive compared to any water savings that may be 
achieved. Regardless of the system employed/ how well the system is 
managed will also affect system efficiency. Irrigation costs 
(1980) for typical irrigation methods in California are summarized 
in Table 6.3. 

Surface (Gravity) Irrigation Systems 

The furrow system is the most common irrigation system used in 
California and is the system of choice for most row crops. In this 
method/ water is conveyed from a head ditch or gated pipe down 
parallel channels or furrows. This system requires a minimum grade 
to maintain an adequate flow rate to assure uniform water 
distribution. Where land is steeply sloping/ furrows are normally 
contoured to the direction of slope. Contouring is not commonly 
used in California. Furrow system design and operation are 
discussed in detail by Bishop et al . , (1967); USDA (1979) and Hart 
(1980). The practical efficiency of this system ranges from about 
70 to 85 percent with a return flow system. 

Border check or border strip irrigation refers to a method where 
water is directed down a gently sloping strip of land bordered by 
dikes. The water advances as a sheet down the strip of land much as 
water down a furrow. This method also often allows for tailwater 



6- 26 



TABLE 6.2 
FACTORS TO CONSIDER IN SELECTING AN IRRIGATION SYSTEMl/ 
(LIMITATIONS IN SYSTEMS) 



Sprinkler Systems 



Factors to Consider 



Handmove 



Surface Flood Systems 

Wheel Solid Center Graded Level 



Roll 



Drip 



Set Pivot Border Border Furrow Systems 



Slope Limitations 

Direction of irrigation 

Cross-slope 

Soil Limitations 

Intake rate (in./hr.) 
Minimum 

Max imum 

Water holding capacity 
in root zone 

Depth 

Erosion hazard 

Saline-alkali soils 

Water Limitations 

Qual i ty 

Total dissolved 
solids (TDS) 

Suspended solids 

Rate of flow 

Climatic Factors 

Temperature control 

Wind affected 

Adaptability to All Crops 

System Costs (1976 data) 

Capital cost ($/acre) 

2/ 



20% 15% None 
20% 15% None 



0.10 0.10 0.05 0.30 
6.0 6.0 6.0 6.0 



3.0 
None 

Slight 
Slight 



Labor cost 



3/ 



Power cost 



4/ 



Average annual cost 
($/acre/year ) 



5/ 



15% 


0.5-4.0% 


Level 


3% 


None 


15% 


0.2% 


0.2% 


6% 


None 



3.0 
None 



None 
None 



2.0 
None 



0.30 
2.0 

6.0 



0.1 
2.0 

6.0 



0.1 
3.0 

4.0 



0.02 
None 

None 



Slight Slight Mod. 
Slight Slight Slight 



Soil should be deep enough None 
to allow for grading reqd. 

Mod. Slight Severe None 

Mod. Slight Severe Mod. 



Severe Severe Severe Severe Slight Slight Mod. Slight 
Mod. Mod. Mod. Mod. None None None Severe 
Low Low Low High Mod. Mod. Mod. Low 



No Yes Yes Yes No 

Yes No No No No 

Fair V.good V.good V.good Good 



No 


No 


Yes 


Yes 


Yes 


yes 


Good 


Good 


Good 



400- 


400- 


700- 


700- 


500- 


500- 


400- 


500- 


600 


600 


1200 


1000 


600 


600 


500 


1200 


High 


Mod. 


Low 


Low 


Mod. 


Mod. 


High 


Low 


High 


High 


High 


High 


Low 


Low 


Low 


Mod. 


100- 


100- 


200- 


200- 


100- 


100- 


200- 


200- 


200 


200 


300 


300 


200 


200 


300 


300 



Application Efficiency 70-85 70-85 75-90 70-85 70-85 75-90 70-85 



80-90 



1/ Source: Prichard, 1980. 

2/ Low = less than $20/ac ./yr . ; moderate = $20-50/ac ./y r . ; high = over $50/ac./yr. 

2/ Low = $0-5/ac./yr . ; moderate = $5-15/ac ./y r . ; high = over $15/ac./yr. 

^_/ Amortized capital cost plus operation and maintenance cost. 

V Assuming good to excellent management. 



6-27 



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6-28 



losses. This technique is primarily used for alfalfa and small 
grains and may also be used for orchards and vineyards. The border 
check method requires accurate leveling. The obtainable efficiency 
of this system ranges from 70 to 85 percent and is primarily dependent 
on proper irrigation management in conjunction with laser leveling 
and a tailwater return system. 

Much of the inefficiency attributable to furrow and border check 
irrigation systems results from tailwater losses at the end of the 
furrow. These tailwater flows are required in order to assure 
adequate intake opportunity time at the end of the furrow. 
Tailwater may be added to drainage ditches, thus increasing overall 
return flows. To avoid tailwater loses, tailwater recovery systems 
should be installed. The design and cost of these systems is 
described by Schulbach and Meyer (1979). 

Another source of inefficiency is the leveling and grading of the 
land. Recent advances in leveling using laser controlled land 
planes assure accuracy of within an inch over a large field. This 
precision combined with proper slope and length of run will result in 
an even water advance rate down the furrow, making irrigation 
management easier. 

Level basin irrigation is probably one of the oldest types of 
irrigation systems, but new technologies have made this system a much 
more attractive option for the westside of the San Joaquin Valley. 
In the San Joaquin Valley approximately 5 percent of the irrigated 
acreage is under level basin systems (California DWR, 1983). In 
Arizona, where much of the current research on this system is being 
conducted, it is used much more extensively. In this system, water 
is rapidly applied to a level field bordered by dikes. All water is 
confined in the basin until infiltrated. This method is similar 
to that used to grow rice in the Sacramento Valley but requires more 
precise leveling. The system is especially suitable for closely 
spaced crops such as alfalfa hay, pasture, and small grains, but can 
be used for row crops such as cotton, sorghum, safflower, and corn. 
Soil topography or the lack of accurate leveling techniques can 
restrict the size of the basins. However, with the level topography 
in the study area and with the introduction of laser leveling, much 
larger and easier to manage fields can be established, thus reducing 
the cost of farm operations. 

The system is especially suited to fine textured soils with lower 
infiltration rates. This allows a higher contact to advance time 
ratio required for more uniform irrigation applications. The 
distribution efficiency of this system has been shown to be as high as 
90 percent on demonstration plots in Arizona (Erie and Dedrick, 
1979). Even though much of the soil on the westside of the San 
Joaquin Valley is fine textured, their extreme shrink-swell 
properties may make this system unsuitable over large areas because 
of the large soil cracks which would restrict irrigation advance 
rates. However, this problem can be overcome by shortening the 



6- 29 



field length/ and thus the advance time (A. R. Dedrick/ personal 
communication). The design and operation of level basin systems are 
described by Erie and Dedrick (1979); Hart ( 1980) ; and Dedrick et al. 
(1982). 

Water is delivered to the level basin in a predetermined volume at a 
prescribed flow rate by means of gates/ lowhead pumps or siphon 
tubes. The advantage of using siphon tubes and pumps is their 
portability. Where the level basin has raised beds for row crops/ 
water delivery should be made from several locations to avoid 
erosion. All furrows are connected at either end by secondary 
ditches to promote rapid water distribution. 

A recent technique for distributing water to level basins, described 
by Dedrick (1984 a, b) , is being used on more steeply sloped lands 
where much cutting and filling would otherwise be required. Plan 
and cross section views of a benched level basin and supply channel 
are shown on Figures 6.7 and 6.8. With this technique, water is both 
conveyed and distributed from the same ditch into bench type level 
basins. The distribution channel follows the natural gradient 
cross-slope and adjacent to the benched basins. When a check is 
placed in the distribution channel, water flows into the level 
basins. When sufficient water has been distributed to the field, 
another check is placed upstream on the channel to flood the next 
higher basin. A variation on this concept that is useful for light 
applications of water is to move checks downstream in the channel to 
allow drainage of water from the basin back into the channel 
(Dedrick, 1983). Regardless of the level basin system used, labor 
requirements are minimal. The primary cost of this system is the 
investment in leveling. 

Sprinkler Irrigation Systems 

In the San Joaquin Valley, sprinkler systems are primarily used in 
orchards, vineyards, and high-value row crops. They can be seen 
more frequently on the eastern side of the San Joaquin Valley where 
the topography is uneven and the soils more suitable for orchards. 
The most common system is the hand-move pipeline comprising about 71 
percent of the sprinkler systems in operation in 1980 in the San 
Joaquin Valley (California DWR, 1983). In the hand-move system, 
water is delivered from sprinkler heads connected to portable 
laterals which are moved periodically down the field. The laterals 
are connected to a main pipeline running alongside the field which 
supplies water under pressure. Although one of the more inexpensive 
irrigation systems due to lower capital investment, the labor and 
energy costs are generally high. Using a side roll sprinkler system 
which operates under the same concept generally reduces the labor 
costs. 

Solid set sprinkler systems rely on sets of fixed laterals. 
Although more expensive to install, they are less labor intensive and 
more easily automated. They are seldom used in the San Joaquin 



6- 30 



r 



Basin 4 




■^ 



Bosin 3 
I I I j 

Basin 
Irrigating 

i M i 



Basin 2 



Basin 
Draining 



I 



^ 



Basin I 



Benches 



-Check 

Gate 

Open 



^_Water 
Flow, 
Supply 
■Road (Barrier Higher Than Water Surface on Basins) Channel 



-Check Gate Open 



CROSS-SECTION 



Bench 



-Natural Slope 



PLAN AND CROSS-SECTIONAL VIEWS OF BENCHED LEVEL BASINS 
IRRIGATED FROM AN UNLINED CHANNEL 

Reference: From Dedrick, igS^. 



BC3L.0B Enctt-iaartnc] CtJirxjrmaan 



FIGURE 6.7 



o 



> ? 




Road 



-Water Surface While Irrigoting 



-Water Surface While Draining 



12 15 18 21 24 27 30 33 

Distance from Rood (Feet) 



CROSS-SECTIONAL VIEW OF UNLINED SUPPLY CHANNEL 
FROM FIELD ROAD TO LEVEL BASIN 

Reference: From Dedrick, 1984. 



Bcxjte Enc3tneennc3 CorfDCjraOon 



6-31 



FIGURE 6.8 



Valley because of the initial capital costs. 

A more recently developed system is the traveler or mechanical move 
system. These include the center pivot system and the linear move 
system. These systems are mechanically very sophisticated but 
require little labor outside regular maintenance. Two major 
problems have limited the utility of the center pivot system in the 
San Joaquin Valley. Because of the circle pattern, land at the 
corners of a field is left unirrigated and soils are subject to 
erosion and runoff because of the high irrigation rates at the 
perimeter of the circle (California DWR/ 1984). The linear move 
system does not have these problems, being able to irrigate the full 
rectangular field with a high degree of uniformity. Instead of a 
stationary water supply as in the center pivot system, the linear 
move system picks up water from a central ditch situated parallel to 
the direction of the moving lateral. This system is being 
increasingly used for row crops. Research on this system is being 
conducted by the Center for Irrigation Technology at California 
State University, Fresno and at Murietta Farms in western Fresno 
County under the direction of the USDA Water Management Laboratory, 
Fresno. For more information on the design and operation of 
sprinkler irrigation systems, refer to Addink et al. (1980), Pair et 
al. (1983), and USDA (1983). More recent advances in sprinkler 
irrigation systems are described by Addink et al. (1980), 

A variation on the linear move irrigation system is the traveling 
trickle irrigation or Low Energy Precision Application system, 
(TTIS) described by Phene et al. (1985) for row crops. This system 
combines the advantages of low-pressure drip irrigation and the high 
uniformity of application provided by the linear-move system. 
Another advantage is that saline water can be applied without foliar 
damage. The system, however, is technically complex and requires 
major capital investment. 

Sprinkler irrigation systems have several advantages over surface 
irrigation systems with respect to irrigation application 
efficiencies. Sprinkler systems can provide a more uniform 
distribution of water to an undulating or sloping field. Sprinkler 
systems can also overcome differences in soil infiltration rates- 
Water application rates can be better controlled to match that part 
of the field with the slowest infiltration rates. Finally, a 
properly designed system will have little runoff. The overall 
efficiency of a sprinkler system is potentially higher than that of a 
surface irrigation system over a wider range of soil conditions, but 
irrigation management decisions play an important role. The 
comparative advantages and disadvantages of sprinkler and surface 
irrigation systems are summarized in Table 6.4. Techniques for 
measuring and evaluating sprinkler irrigation systems are 
summarized by Criddle et al. (1956) and Merriam and Keller (1978). 



6- 32 



TABLE 6.4 

ADVANTAGES AND DISADVANTAGES OF SPRINKLER 
RELATIVE TO SURFACE IRRIGATION SYSTEMSl/ 



Advantages Disadvantages 

o Can be used on porous and o Initial cost can be high, 
variable soils. 

o Energy costs are higher than 

o Can be used on shallow soil for surface systems, 
prof i les . 

o Higher humidity levels can 

o Can be used for rolling increase disease potential 

terrain. for some crops. 

o Can be used on easily o Sprinkler application of 

eroded soils. highly saline water can 

cause leaf burn, 
o Can be used with small flows. 

o V'Jater droplets can cause 

o Can be used where high blossom damage to fruit 

water tables exist. crops or reduce the quality 

of some fruit and vegetable 

o Can be used for light, crops, 
frequent applications. 

o Portable or moving systems 

o Control and measurement can get stuck in some clay 

of applied water are easier. soils. 

o Tailwater control and o Higher levels of pre-appli- 
reapplication are minimized. cation treatment generally 

are required for sprinkler 
systems than for surface 
systems to prevent operating 
problems (clogging). 

o Distribution is subject to 
wind distortion. 

o Wind drift of sprays in- 
creases the potential for 
public exposure to waste- 
water . 



1/ Source: Smith et al . , (1984) 



6-33 



Drip/Trickle Irrigation Systems 

Drip/trickle systems were first introduced into California in the 
mid to late 1960 's for irrigation of avocados in San Diego County. 
By 1980, drip/trickle systems were being used on about 2.4 percent of 
the irrigated acreage in California (California DWR, 1983). In this 
system, carefully filtered water is applied continuously or as 
pulses from perforated plastic tubing or emitters attached to 
flexible plastic tubing. Only a portion of the soil mass is 
irrigated. A properly designed system will apply water uniformly 
and at a rate to meet the crop peak water demand. An evaluation of 
trickle irrigation systems in the San Joaquin Valley found that 
improper maintenance contributed to significantly decreased 
irrigation efficiency (Fry, 1985). 

Although costly to install, drip systems are potentially the most 
efficient of irrigation systems because they are highly automated 
and the control of the irrigation rate is very precise. 
Drip/trickle systems are primarily used for permanent crops such as 
trees and vines where cultivation does not require movement of the 
lines. However, recently the use of drip systems in row crops has 
been advanced. Two approaches have been tried to overcome the 
annual rotational problem of row crops. One method involves rolling 
up the surface drip lines on a large spool after the irrigation 
season. The other method involves burying the drip lines at a 
specified depth in the soil under the bed to prevent any damage from 
field operations (Tollefson, 1985). More information on the 
installation, operation, and maintenance of drip/trickle systems 
can be found in Howell et al . (1985), March et al . (1979), and Pair et 
al. (1983). 

Subsurface Irrigation Systems 

In California subsurface irrigation is primarily employed on the 
peat soils of the Sacramento-San Joaquin Delta. These lands are 
located in islands separated from surrounding waterways by levees. 
Since the elevation of these lands is below that of the surrounding 
water, crops are irrigated by allowing the water table to rise to a 
certain depth below the root zone. This technique is facilitated by 
digging spud ditches at certain intervals in the field. Water 
levels are controlled by pumping excess water from the islands back 
into the adjoining water courses. 

There is very little managed subsurface irrigation in the project 
area. Its occurrence is primarily in areas with poor drainage and 
consequently where there is a shallow and saline perched water table. 
Managing this shallow water table to partially meet the water 
requirements of cotton has been under investigation by several 
researchers in the San Joaquin Valley. (See Section 6,3.4). 



6-34 



6.3 WATER REUSE 

One of the alternatives that can be used to reduce subsurface 
drainage flows in the western San Joaquin Valley is reuse as 
irrigation water. In water districts where irrigation return flows 
are redirected into the water distribution system this is already 
being accomplished. In the Broadview Water District in western 
Fresno County, approximately 50 percent of the surface water supply 
comes from the Del ta-Mendota Canal and the remaining 50 percent from 
return flows recirculated back into the district irrigation canals 
(Tanji, 1976 and 1977 as cited in Ayars and Westcot, 1985). Between 
1956 and 1982 this district reused all its surface and subsurface 
drainage waters because the district did not have an outlet. Since 
1982, however, decreasing water quality (from salinity) has resulted 
in the development of an outlet and the discharge of about 20 percent 
of the subsurface drainage water from the district. The decreasing 
blended water supply quality over the years is reflected in a 
cropping pattern change from largely tomatoes to one of 
predominately barley and cotton (Ayars and Westcot, 1985). 




The technology applied to recover and reuse subsurface drainage 
water is essentially the same as that used to recover and reuse 
tailwater (Schulbach and Meyer, 1979; and Hart et al., 1980). A 
tailwater recovery system requires a suitable drainage water 
receiving facility such as a sump or a holding pond that can be used 
for storage/blending purposes. Additional requirements are a pump 
and pipelines to return the drainage water for reapplication . In 
combination with a gated pipe delivery system, total irrigation 
costs may be less than for a furrow irrigation system with siphons and 
no reuse system (Kinney et al . , 1977). Engineering assistance for 
drainage water return system design and construction is available 
from the SCS and private consultants. 

The primary limitation of applying agricultural drainage water for 
irrigation is water quality. Water quality criteria for 
agriculture have been discussed extensively by Ayars (1977), 
Shainberg and Oster (1978), Westcot and Ayars (1985), and Ayars and 
Westcot (1985). The quality of tailwater is usually quite different 
than subsurface drainage water. Tailwater may be degraded with 
sediments, nutrients, and pesticides while salinity may not be much 
greater than in the irrigation water. Subsurface drainage water, 
however, has passed through the soil profile accumulating soluble 
nutrients (especially nitrate-nitrogen) and inorganic salts 
including trace elements. 

Agricultural water quality criteria are established in order to 

6- 35 



determine irrigation water suitability for growing crops and to 
predict the effect of irrigation water quality on crop yield, and 
soil physical and chemical properties (Table 6.5). If blended 
irrigation water salinity exceeds crop salt tolerance levels, yield 
reductions may result or irrigation management costs may 
significantly increase. This is usually not a problem with 
tailwater reuse since tailwater is often applied without blending 
because of its typical low salinity. In cases of very saline 
subsurface drainage water, the ratio of irrigation water to 
subsurface drainage water may be so high it makes blending 
impractical. Water reuse must be evaluated in consideration with 
crop salt tolerance levels, economics and leaching requirements. 
Leaching requirements will increase because of the higher salinity 
of blended water. 

Four general approaches can be followed to reuse surface and 
subsurface drainage waters: 1) direct application without 
blending; 2) blending poor quality saline waters with good quality 
non-saline surface irrigation supplies; 3) using saline drainage 
water or blended water when plants are least susceptible to salt 
injury; and 4) using shallow saline groundwaters to satisfy a portion 
of the crop water requirement. Each approach requires different 
management considerations. 

5.3.1 Reuse Without Blending 

In most instances, subsurface drainage waters are too saline to apply 
for irrigation without blending with good quality non-saline 
irrigation water. An exception is the experimental work being 
performed by Rhoades (1983 and 1984) where saline waters are applied 
during salt tolerant crop growth stages. This work is discussed in 
Section 6.3.3. Presently, reuse without blending is generally 
restricted to the recycling and application of tailwaters. This 
practice is followed on some farms but generally where tailwater is 
reused it is discharged into the irrigation water distribution 
facility and then reapplied in conjunction with fresh irrigation 
water. This approach increases tailwater losses through conveyance 
system inefficiencies, evaporation, and ET of ditch bank vegetation. 
However, this approach does facilitate water conservation. The 
efficient application of tailwater will result from a properly 
designed system that includes provisions for collection, storage and 
application. In practice, tailwater flows are collected at the end 
of the field, transported to a small reservoir, and then piped back to 
the same field or another field. Incidental blending probably 
occurs during the reapplicat ion process. Costs associated with 
implementing a tailwater reuse program will vary based on the 
cropping patterns, method of irrigation, existing field 
configuration, and design considerations. Initial construction 
costs can be reduced if the system is implemented in conjunction with 
other improvements that require land leveling. In addition to the 
annual fixed cost component, annual variable costs will also 
increase based on higher operational and maintenance inputs. 



6- 36 



TABLE 6.5 

GUIDELINES FOR INTERPRETATIONS OF 

WATER QUALITY FOR IRRIGATION!/ 



Degree of Restriction on Use 
Potential Irrigation Problem Units None Slight to Moderate Severe 

Salinity (affects crop water 
avai lability ) 2^/ 
ECw dS/m <0.7 0.7-3.0 >3.0 

(or) 
TDS mg/1 < 450 450 - 2000 > 2000 

Infiltration (affects infiltration 

rate of water into the soil. 
Evaluate using ECw and SAR 
together )2/ 

SAR = 0-3 and ECw = > 0.7 0.7 - 0.2 < .02 

= 3-6 = > 1.2 1.2 - 9.3 < 0.3 

=6-12 = >1.9 1.9-0.5 <0.5 

=12-20 = >2.9 2.9-1.3 <1.3 

=20-40 = > 5.0 5.0 - 2.9 < 2.9 

Specific Ion Toxicity (affects 
sensitive crops) 

Sodium {Na)£/ 

surface irrigation SAR < 3 3-9 > 9 

sprinkler irrigation me/1 < 3 > 3 

Chloride (Cl)£/ 

surface irrigation me/1 < 4 - 10 > 10 

sprinkler irrigation me/1 < 3 > 3 

Boron (E)S/ mg/1 < 0.7 0.7 - 3.0 > 3.0 

Miscellaneous Effects (affects 
susceptible crops) 

Nitrogen (N03 - N)6^/ mg/1 < 5 5-30 > 30 

Bicarbonate (HC03) 
(overhead sprinkling only) rae/1 < 1.5 1.5 - 8.5 > 8.5 

pH Normal Range 6.5 - 8.4 



1/ Adapted from University of California Committee of Consultants, 1974. 

2/ ECw means electrical conductivity, a measure of the water salinity, reported in 
deciSiemens per meter at 25 degrees C (dS/m) or in millimhos per centimeter (mmho/cm) . 
Both are equivalent. TDS means total dissolved solids, reported in milligrams per 
liter (mg/1) . 

2/ SAR means sodium adsorption ratio. SAR is sometimes reported by the symbol RNa. See 
Figure 1 for the SAR calculation procedure. At a given SAR, infiltration rate 
increases as water salinity increases. Evaluate the potential infiltration problem 
by SAR as modified by ECw. Adapted from Rhoades 1977, and Oster and Schroer 1979. 

£/ For surface irrigation, most tree crops and woody plants are sensitive to sodium and 
chloride; use the values shown. Most annual crops are not sensitive; use the salinity 
tolerance tables (Tables 4 and 5). For chloride tolerance of selected fruit crops, 
see Table 14. With overhead sprinkler irrigation and low humidity {<30 percent), 
sodium and chloride may be absorbed through the leaves of sensitive crops. For crop 
sensitivity to absorption, see Tables 18, 19, and 20. 

5/ For boron tolerances, see Tables 16 and 17. 

6/ N03-N means nitrate nitrogen reported in terms of elemental nitrogen (Nh4-N and 

~ Organic-N should be included when wastewater is being tested). 



6-37 



Table 6.5, continued 

Assumptions in the Guidelines 

The water quality guidelines in Table 6.5 are intended to cover the wide range of 
conditions encountered in irrigated agriculture. Several basic assumptions have been 
used to define their range of usability. If the water is used under greatly different 
conditions, the guidelines may need to be adjusted. Wide deviations from the assumptions 
might result in wrong judgements on the usability of a particular water supply, especially 
if it is a borderline case. Where sufficient experience, field trials, research or 
observations are available, the guidelines may be modified to fit local conditions more 
closely. 

The basic assumptions in the guidelines are : 

Yield Potential : Full production capability of all crops, without the use of special 
practices , Ti assumed when the guidelines indicate no restrictions on use. A 
"restriction on use" indicates that there may be a limitation in choice of crop, or special 
management may be needed to maintain full production capability. A "restriction on use" 
does not indicate that the water is unsuitable for use. 

Site Conditions : Soil texture ranges from sandy loam to clay loam with good internal 
drainage. The climate is semi-arid to arid and rainfall is low. Rainfall does not play a 
significant role in meeting crop water demand or leaching requirement. (In a monsoon 
climate or areas where precipitation is high for part or all of the year, the guideline 
restrictions are too severe. Under the higher rainfall situations, infiltrated water 
from rainfall is effective in meeting all or part of the leaching requirement.) Drainage 
is assumed to be good with no uncontrolled shallow water table present within 2 meters of 
the surface. 

Methods and Timing of Irrigations : Normal surface or sprinkler irrigation methods are 
used. Water is applied infrequently, as needed, and the crop utilizes a considerable 
portion of the available stored soil-water (50 percent or more) before the next 
irrigation. At least 15 percent of the applied water percolates below the root zone 
(leaching fraction (LF1>^ 15 percent) . The guidelines are too restrictive for specialized 
irrigation methods such as localized drip irrigation which results in near daily or 
frequent irrigations, but are applicable for subsurface irrigation if surface applied 
leaching satisfies the leaching requirements. 

Water Uptake by Crops : Different crops have different water uptake patterns but all 
take water from wherever it is most readily available within the rooting depth. On 
average, about 40 percent is assumed to be taken from the upper quarter of the rooting 
depth, 30 percent from the second quarter, 20 percent from the third quarter, and 10 
percent from the lowest quarter. Each irrigation leaches the upper root zone and 
maintains it at a relatively low salinity. Salinity increases with depth and is greatest 
in the lower part of the root zone. The average salinity of the soil-water is three times 
that of the applied water and is representative of the average root zone salinity to which 
the crop responds. These conditions result from a leaching fraction of 15 to 20 percent 
and irrigaitons that are timed to keep the crop adequately watered at all times. 

Salts leached from the upper root zone accumulate to some extent in the lower part but a 
salt balance is achieved as salts are moved below the root zone by sufficient leaching. 
The higher salinity in the lower root zone becomes less important if adequate moisture is 
maintained in the upper, "more active" part of the root zone and long term leaching is 
accomplished . 

Restriction on Use : The "Restriction on Use" shown in Table 6.5 is divided into three 
degrees of severity: none, slight to moderate, and severe. The divisions are somewhat 
arbitrary since change occurs gradually and there is no clear cut breaking point. A 
change of 10 to 20 percent above or below a guideline value has little significance if 
considered in proper perspective with other factors affecting yield. Field studies, 
research trials and observations have led to these divisions, but management skill of the 
water user can alter them. Values shown are applicable under normal field conditions 
prevailing in most irrigated ares in the arid and semi-arid regions of the world. 



6-38 



Assuming a properly designed system, irrigation efficiencies as high 
as 85 to 90 percent are achievable with this approach. The impact of 
reusing tailwater without blending on subsurface drainage water 
quality will be negligible with the magnitude of drainage flow 
reduction based on the amount of the irrigation efficiency 
improvement . 

6.3.2 Reuse With Blending 

With this alternative, poor quality saline waters are blended with 
good quality irrigation water in a proportion such that the salinity 
of the blended water is within the crop salt tolerance limit. 
Careful measurement and control of each water supply is needed. 
With blended irrigation waters, there is little flexibility in being 
able to use the better quality water for germination and seedling 
establishment or for more salt sensitive crops because of the higher 
salinity (Rhoades, 1984). The facilities required are similar to 
those used for tailwater reuse; however, provisions are also needed 
for blending purposes. Thus, the facilities cost will be higher 
compared to those needed solely for tailwater return. This approach 
may not be practical for highly saline waters because of the required 
high fresh to drainage water blending ratio. However, reuse, where 
applicable, coupled with improvements to facilitate irrigation 
efficiency could substantially reduce drainage flows. Even where 
current soil and water conditions would allow, drainage water reuse 
is a short term solution unless a salt balance can be maintained. 
The reuse alternative does not mean operation using a closed system. 
The collection and disposal of saline waters would need to occur or 
crop salt tolerance levels would eventually be exceeded. 

6.3.3 Irrigation Water Salinity Versus Crop Growth Stage 

With this alternative, poor quality saline water is substituted for 
good quality irrigation water during the least salt-sensitive crop 
growth stage, or when the more salt tolerant crop is planted. This 
approach is suited to flood/furrow irrigation techniques which do 
not allow water contact on the foliage. Plant injury could result 
from sprinkler irrigation with saline waters. 

Investigations of the best management strategy for irrigating crops 
with water of different qualities is being explored by James Rhoades 
of the USDA Salinity Laboratory (Rhoades, 1983 and 1984) at locations 
in the Imperial and San Joaquin Valleys. Rhoades' primary objective 
is to minimize subsurface drainage flows by recycling saline 
drainage waters while not seriously impacting soil salinity levels 
and restricting crop growth. The strategy involves irrigating with 
good quality water until a crop is germinated and a stand is 
established and then substituting more saline drainage waters during 
the salt tolerant stages of plant growth. With this strategy, wheat 
and cotton have been successfully grown with 3500 and 6000 mg/1 TDS 
drainage waters, respectively following seedling establishment 
(Rhoades, 1984). Another advantage of this system is that precise 



6- 39 



controls and measurement needed for blending are not necessary. 

6.3.4 Subsurface Irrigation 

Under conditions where a shallow groundwater table is located in 
close proximity to the soil surface, this water may contribute to the 
crop water requirements. This in effect reverses deep percolation 
losses. The upward movement of water into the root zone as it is 
depleted by crop ET occurs by capillary movement. 

Significant reductions in deep percolation may be achieved by using 
shallow saline ground waters to satisfy a portion of the crop water 
requirement. The amount of uptake depends on water table depth and 
salinity of the soil profile. Optimum management strategy would 
require an ability to control the depth of the water table and 
irrigation with sufficient low salinity water, in particular during 
early crop growth, to maintain soil salinity below the threshold 
established for crop tolerance. Facilities do not exist in the 
study area that would allow optimum management strategy. However, 
the opportunity exists to use the shallow water table to provide a 
part of crop ET. This is especially true for crops like cotton and 
safflower. Conceptually, permanent tree plantings, i.e. eucalyp- 
tus, could be used to control shallow water table depth. 

6.4 CROP MANAGEMENT 

Crop management practices must be modified to address requirements 
for the on-farm management alternatives which may be implemented to 
reduce subsurface drainage flows. Improving irrigation efficiency 
increases the possibility of creating plant stress, either from 
insufficient soil moisture during part of the growing season or 
increased salinity-induced stress from inadequate salt leaching. 
Certain crop management practices are available that will assist to 
improve plant stress factors caused by increasing irrigation 
efficiencies. These include improved cultural practices and 
selection of crops better adapted to soil moisture and salt stresses 
which may result from more efficient irrigation practices. 

The planting of crops that are more salt/boron tolerant may also be 
required to address increased concentrations of these constituents 
that may result from water reuse. Silviculture is another potential 
approach which may be used for highly saline drainage waters to 
reduce drainage water volumes for disposal purposes. Alternative 
cropping approaches must be evaluated in terms of their ability to 
compete economically with existing cropping patterns. Crop 
management practices including fallowing, crop selection, and 
others are a means to achieve a reduction in subsurface drainage 
flows. The management practices implemented will depend on the 
characteristics of individual farming operations. 



6- 40 



6.4.1 Cultural Practices 

Cultural practices can be modified to improve crop water use 
efficiency or to avoid salinity problems created by increasing 
irrigation efficiency. Cultural practices that could facilitate 
irrigation water use efficiency include increasing plant density/ 
variable plant/row spacing, shortening the growing season, using 
transplants and allowing land to remain fallow. Cultural practices 
that could facilitate crop tolerance to salinity include adjusting 
seed placement, changing bed shape, and irrigation water management. 

The effect of narrow row planting of cotton, i.e., 30 inches versus 40 
inches, on water use efficiency was studied by Howell et al., (1984). 
Narrow row cotton planting was suggested as an alternative where crop 
growth is limited by environment such that plant cover is not 
maximized. They observed that the narrow row cotton had increased 
yield and water use efficiency under similar irrigation treatments. 
However, based on study area experience, this approach when 
attempted on high shrink/swell soils, will greatly reduce the 
efficiency of pre-irr igat ion . 

Another concept is to use variable plant spacings with furrows 
between every other row. With this concept, spacings are 
alternately 34 and 46 inches. This system is used for cotton in west 
Texas and has been found to require less water. Other beneficial 
effects are reported to be less crop salt injury problems and more 
rapid wetting of the root zone during irrigation because of the close 
proximity of the rows to the furrow. This approach also results in 
fewer weed problems and less evaporation from the furrow because of 
more rapid canopy closure (Moore, 1985). 

Earlier planting may encourage use of soil moisture retained from 
winter rains and pre-irrigation . In general, though, this 
alternative has very limited potential since most planting is done as 
soon as soils are workable in the spring planting period and when 
soils are sufficiently warm. Planting too early would subject 
plants to cold wet soils which may result in poor germination and 
increased disease problems. Earlier winter wheat planting, 
however, may be possible with earlier cotton harvesting. 

Growing crops from transplants has also been suggested as a method to 
reduce the number of irrigations, especially the first irrigation 
which may be the most inefficient due to lack of sufficient root 
development. A pre-irrigation is also unnecessary if irrigation 
immediately follows transplanting. Although used for vegetables on 
high value land, this method is presently too expensive for row crops 
grown in the San Joaquin Valley. New techniques to automatically 
plant seedlings may reduce the high labor costs involved with this 
operation (Ventura Manufacturing, Inc.). 

The most drastic cultural practice that may be used to reduce deep 
percolation to the shallow groundwater is to let the land lie 



6- 41 



permanently fallow. In most years, there is insufficient rainfall 
on the west side of the San Joaquin Valley to fill the soil profile 
sufficiently to cause deep percolation. However, if the water table 
is close to the soil surface, evaporation losses of water may occur 
causing salinization of the soil surface which then would 
necessitate expensive reclamation of the soil before crops could 
again be grown. In addition, it may be more economical to grow a crop 
at a loss than to let land lie fallow because of fixed costs 
associated with land mortgages, payments for equipment, general 
maintenance, and depreciation. 

Several cultural practices can be used to reduce the effects of soil 
salinity on germinating crops under furrow irrigation. With furrow 
irrigation, as water moves toward the center of the bed, salts in the 
soil will move toward the upper center of the bed where evaporation is 
greatest. To avoid salt injury to seedlings, seed placement can be 
moved to the side of a bed or as a double row on a bed. Another 
approach for a single seed row is to irrigate every other furrow 
during early growth stages so that salt accumulation is toward the 
unirrigated furrow. The relationship of seed placement to salt 
accumulation is illustrated in Figures 6.9 and 6.10. 

6.4.2 Crop Selection for Increased Irrigation Efficiency 

Some crops, either because of their growth characteristics or 
associated cultural practices, achieve a more efficient use of 
available water supplies than other crops. Irrigation efficiencies 
and deep percolation losses for crops grown in the San Joaquin Valley 
under typical water application rates are estimated in Table 6.6. 
Those crops which are the most efficient water users are not 
necessarily crops with the lowest water requirement. As an example, 
alfalfa, which requires approximately 41.8 inches of water during 
its annual growing season, has a typical irrigation efficiency of 
about 71 percent as opposed to cantaloupes which have a water 
requirement of only 13.2 inches but an irrigation efficiency of about 
33 percent. This difference is largely the result of crop growth 
characteristics, inherent soil physical properties, irrigation 
methods appropriate for a specific crop, and cultural practices 
associated with crop production. If this is the case, then due 
consideration must be made to continue cultivation of these crops if 
improved irrigation efficiencies are not achievable. 

Another alternative is to select crop varieties with either shorter 
growing seasons or more extensive rooting systems. Crop varieties 
with shorter growing seasons offer the advantage of lower overall 
water requirement which could equate to fewer irrigations and thus 
deep percolation losses would be less than long season varieties. 
An economic comparison must be made since reductions in crop growing 
season length are typically associated with lower yield potential. 
Crop varieties with more extensive rooting systems may be able to 
more effectively use applied irrigation water or take advantage of 
shallow groundwater thus reducing deep percolation losses. Costs 



6- 42 



SINGLE 

ROW BED ^El 



X- 



^U 






DOUBLE 

ROW BED =^ 



4^4^ 



Sou occumulotion 




^ 



^ \^ 



SALT MOVEMENT BASED ON FLAT TOP BEDS AND 
IRRIGATION PRACTICE 



Reference: From Bernstein, Fireman and Reeve, 1975. 



BoL^e . 



> CorpHDcaaon 



FIGURE 6.9 



J 




SINGLE- ROW 
SLOPING BED 



DOUBLE -ROW 
SLOPING BED 



SALINITY CONTROL WITH SLOPING BEDS 



Reference: From Bernstein and Fireman, 1957. 



Boute Encjlnsmmo Corpxji'aaon 



FIGURE 6 



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6-43 



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6-44 



of implementing this alternative would be minimal. Even though 
yield reductions may be incurred by using this approach, shorter 
growing season crops may require less labor and mechanical inputs 
thereby resulting in a beneficial alternative cropping practice. 

Considerable interest has been directed toward crops which could 
reduce or even reverse deep percolation losses. These crops are 
expected in this management strategy to rely on shallow groundwaters 
for all or part of their water requirement. Examples of such crops 
that can be grown in the San Joaquin Valley include cotton (Wallender 
et al., 1979; Hanson and Kite, 1984; and Grimes et al., 1985), corn 
(Follett et al., 1974; and Kruse et al., 1985), alfalfa (Follett et 
al., 1974; and Benz et al., 1981), sugar beets (Follett et al., 1974), 
wheat (Chaudhary et al., 1974), and lettuce (Shih and Rahi , 1984). 
Expected limitations are the tolerance of these crops to groundwater 
salinity and the more restricted rooting volume. Further 
discussion of the management of shallow groundwater tables as a 
supplemental source of water for crops can be found in sub-section 
6.3.4. 

It has been proposed that woody plant species be grown on high water 
table soils on the west side of the San Joaquin Valley with the intent 
of using the biomass produced by these plants as a fuel source, either 
directly as firewood or as wood chips for electrical cogeneration 
facilities. Primary interest has been directed toward the 
eucalyptus species, in particular the salt tolerant E. 
camaldulensis , because of its ability to grow in areas with shallow 
saline water tables in Australia (Biddiscombe et al., 1981; and 
Morris, 1984). However, data are not available to determine the 
contribution of the shallow water table to the crop water 
requirement, let alone the quantity of water transpired by the crop. 
The primary intent of this management practice is to lower the water 
table sufficiently to prevent excess salinization of the upper soil 
profile by capillary rise in areas with established crops and 
pastures (Morris and Thomson, 1983; and Morris, 1984). Eucalyptus 
and other tree species are being evaluated by the SCS at Murietta 
Ranch in Westlands Water District. Trees may provide an alternative 
to evaporation ponds required for on-farm subsurface drainage water 
disposal. The tree planting would remove water by ET thus reducing 
the subsurface drainage water volume. An evaporation basin would 
still be needed in the system for brine disposal. 

Evapotranspiration by eucalyptus has been measured indirectly by the 
water budget method (Karschon and Heth, 1967) and directly by using a 
ventilation chamber technique (Greenwood and Beresford, 1979), but 
calculated ET varies depending on species, stage of growth, soil 
moisture characteristics, and other environmental factors. 
Potential ET data for eucalyptus under optimum growing conditions 
are not readily available; however, estimates range from 5 to 7 feet. 

The cost of establishing a stand of eucalyptus has been estimated to 
range from $1,000 to $2,000 per acre and includes the cost of soil 



6- 45 



preparation; fertilizing/ growing seedlings in nurseries/ planting, 
irrigating/ weed control/ etc. (Randy Godden/ SCS/ DaviS/ 
California/ personal communication). A range of costs for 
eucalyptus firewood plantings for the first three years is shown in 
Table 5.7. Yields of several species of eucalyptus grown in 
California were summarized by Metcalf (1924) cited in Standiford et 
al . , ( 1984) . The yield for E^ camaldulensis ranged from .038 to 2.80 
cords/acre/year. The yield of the fast growing, but salt sensitive 
E. globulus (southern blue gum)/ which was the most frequently 
planted eucalyptus in California, was .045 to 6.76 cords/acre/year. 
More recently/ Standiford/ et al. (1984) predicted that over a 10 
year period E_^ globus would yield an average of 25, 47/ and 79 cords 
per acre for poor, medium/ and. high quality sites/ respectively. 
Based on Godden 's estimated price for eucalyptus fuel wood at 
$85/cord/ the gross return from the highest quality site would 
average about $671/year. An effective salt management program 
would be needed to maintain optimum yield. Other markets for 
eucalyptus include woodchips for fuel. 

TABLE 6.7 
RANGE OF COSTS EXPECTED FOR 
EUCALYPTUS FIREWOOD PLANTINGSl/ 



Cost Item 



Year(s) in Which 

Cost Occurs Range of Costs 



Seedlings 

Site preparation 

Planting 

Irrigation 

Weed control 

Fencing 

Harvest/ cut 

and stack/ etc, 

Transportation 

Property tax 

Income tax 

Interest 



1st year 
1st year 
1st year 
Variable 
1st to 3rd year 
1st year 
At harvest 

At harvest 

Annual 
At harvest 

Annual 



$135 - $480/acre 

$ 60 - $300/acre 

$ 60 - $150/acre 

$0 - $300/acre/year 

$30- $100/acre/year 

$0 - $2400/acre 

$ 35 - $70/cord 

$1.50-$3.50/cord/mile 
Variable 
Variable 
Variable 



1/ Source: Standiford et al/ (1984). 



6- 46 



Another woody species that has received attention in the 
southwestern United States is mesquite ( Prosopis glandulosa ) , a 
leguminous desert phreatophyte growing on saline desert soils. 
Mesquite relies primarily on groundwater for most of its water supply 
and can tolerate groundwater salinities up to 18,500 ppm TDS (Jarrell 
and Virginia, 1985). Water consumption by mesquite was estimated by 
Nilsen et al. (1981) to be as high as 26.2 inches/year in the 
California Sonoran desert. Biomass production of mesquite near 
Harper's well in Southern California has been estimated to average 
3,650 kg/ha/year (Sharifi et al., 1982) and production of 12,700 
kg/ha/year of leaves and pods has been reported for a species of 
mesquite growing in Chile (Salinez and Sanchez, 1971). In addition 
to its value as a fuel source, mesquite also provides an excellent 
habitat for honey production. 

Other desert phreatophytes that could find potential use in the San 
Joaquin Valley are Tamarix chinesis , Olneya tesota , and Acacia 
gregg i i . Tamarix (salt cedar) has long been considered a pest along 
waterways because of its high consumptive use of groundwater. 
Davenport et al., (1982) measured the transpiration rates of salt 
cedar grown in lysimeters in Davis, California for typical summer 
days and found that a moderately dense stand of salt cedar transpired 
about 0.26 inches/day while a dense stand transpired about 0.62 
inches/day. These values will be less at other times of the year 
when there is inadequate moisture supply or if soils are saline. 
These authors also referred to reports of seasonal ET rates of salt 
cedar ranging from 4 to 10 feet per year. This characteristic may be 
useful in the drainage problem area although salt cedar wood is 
reportedly inferior to hardwood species such as eucalyptus. 

With all cropping systems that rely on groundwater for a portion of 
their water supply, an increase in soil salinity would be expected 
unless soils are periodically leached. Short term advantages from 
phreatophytes would be a lowering of the salinity in the upper soil 
profile from rainfall and limited irrigation. A water table 
maintained at a sufficient depth would prevent capillary rise of 
saline waters to the upper soil profile where it would be 
concentrated. An effective long term salt management system must be 
maintained to prevent salt stress. 

6.4.3 Crop Selection for Salt/Boron Tolerance 

Plants vary widely in their response to salinity. Most principle 
agricultural crops are intolerant to moderate to high levels of salts 
and are categorized as glycophytes. Salt tolerant plants, or 
halophytes, have developed particular adaptations to saline 
environments. There are those plants that are able to keep salts out 
of their tissues, such as alkali bullrush, and those that maintain a 
high osmotic potential in their tissues by absorbing salts with the 
water. Plants in this category, which include many species of 
chenopodia, such as pickleweed ( Salnicornia virginica ), maintain a 
salt balance by excreting salt from their leaves. 

6- 47 



with increased soil salinity brought about from more efficient 
irrigation practices and accumulation of salts from shallow 
groundwater tables at or near the soil surface, increased attention 
has been directed toward substituting more salt tolerant species and 
varieties of crops in the drainage problem areas of the San Joaquin 
Valley. Currently, some of the most salt tolerant crops already 
constitute a large portion of the cropped agricultural land on the 
west side of the San Joaquin Valley, in particular, cotton and 
barley. Sugar beets are also quite salt tolerant, but production 
has been greatly diminished because of depressed sugar prices. 
Moderately salt tolerant crops found on the westside include wheat 
and sorghum. 

Threshold salinity levels and expected yield reductions with 
increased salinity are summarized in Table 6.8 for selected 
agricultural crops grown in the western San Joaquin Valley. Percent 
yield reduction, Y, is calculated from the following equation: 

Y = 100 - B (ECe - A) [6.7] 

where A is the salinity threshold, B is the percent yield decline per 
unit salinity (1 mmho/cm) increase above the threshold, and ECe is 
the electrical conductivity (in mmhos/cm) of the saturated extract. 
In gypsiferous soils, the threshold salinity level may be 
approximately 2 mmhos/cm higher than indicated in Table 6.8. The 
tolerance rating of a crop can be determined by plotting the ECe 
versus the percent yield declines (see Figure 6.11). 

With increasing soil salinity that may result from increasing 
irrigation efficiency, changes to more salt tolerant crops may be 
required to avoid yield decreases and lost income. Changing to a 
more salt tolerant crop may not always provide a solution if this 
alternative crop is less profitable to grow. 

Crop tolerance to salinity will vary depending on the growth stage. 
For many crops the most sensitive period is during emergence and 
early growth. Examples for crops commonly grown in the San Joaquin 
Valley are summarized in Table 6.9. The increased sensitivity of 
crops during emergence and early growth may require leaching excess 
salts from the upper soil profile with non-saline water prior to 
seeding. Alternating non-saline and saline waters during the crop 
growing season is being studied by Rhoades (1985). 

Another problem associated with saline soils of the western San 
Joaquin Valley is high boron concentrations with values reported 
from 1.0 to 36 ppm in drainage waters (California DWR, 1984). These 
levels are generally well above the boron tolerance of all but the 
most tolerant crops. Therefore, crop tolerance to boron should be 
considered before planting crops on soils with high boron levels or 
when irrigating with high boron water. The maximum concentrations 
of boron tolerated by selected agricultural crops grown in the 



6- 48 



TABLE 6.8 
SALT TOLERANCE OF AGRICULTURAL CROPS GROWN 
IN THE WESTERN SAN JOAQUIN VALLEYl/ 



% Decrease 
Salt in Yield 
Tolerance^/ with Salinity V 
Threshold(A) Above Threshold(B) Tolerance 
Crop (mnihos/cm)4/ %/ (mmhos/cm) 5/ Rating 



7.1 MT 

7.6 MT 

4.3 MT 

2.6 MT 
7.3 



5.0 T 
5.2 T 

12.0 MT 

16.0 MT 

20.0 MT 

5.9 T 

7.1 MT 



2.0 T 

9.0 MT 

9.4 MT 

Permanent Crops 

Date palm 4.0 3.6 T 

Fig - - MT 

Almond 1.5 19 

Pistachio 



Forage Crops 




Salt grass 




Barley 


6.0 


Ryegrass 


5.6 


Sudangrass 


2.8 


Wheat 


4.5 


Alfalfa 


2.0 


Field Crops 




Barley 


8.0 


Cotton 


7.7 


Cowpea 


4.9 


Sorghum 


6.8 


Soybean 


5.0 


Sugar beet 


7.0 


Wheat 


6.0 


Truck Crops 




Asparagus 


4.1 


Red beet 


4.0 


Zucchini 


4.7 



V Maas, E.V. 1986. Salt Tolerance of Plants in Applied 
Agricultural Research, Vol. 1, No. 1, pp. 12-26. 

2^/ The mean soil salinity at initial yield decline. 

"3/ Ratings are determined by boundaries in Figure 6.11. 

4/ Electrical conductivity of saturated extracts (1 mmhos/cm= 
approximately 640 mg/L salt). 

5/ Percent yield decrease per salinity unit (1 mmho/cm) above 

~ salt tolerance threshold. 



6-49 



r 



100 



T — TT — TT — I — 1 — I — I — I — I — I — I — 1 — 1 — I — I I — T"" — ' — ' — T 




Electrical Conductivity 
of Soil Saturation Extract (mmhos/cm) 



DIVISIONS FOR QUALITATIVE SALT-TOLERANCE 
RATINGS OF AGRICULTURAL CROPS 



Reference: From Maas and Hoffman, 1977. 

Note: Symbols given compare with those in Table 6.8. 



Bcxje . 



I CarxjraOi D i i 



FIGURE 6.11 



6-50 



TABLE 6.9 

SALT TOLERANCE OF SELECTED CROPS GROWN IN THE 
SAN JOAQUIN VALLEY AT 
EMERGENCE AND DURING GROWTH TO MATURITYl/ 



Electrical Conductivity 
of Saturated Extract 

(mmhos/cm) 

Crop 50% Yield 2/ 50% Emergencel/ 

Barley 18 16-24 

Cotton 17 15 

Sugar beets 15 6-12 

Sorghum 15 13 

Safflower 14 12 

Wheat 13 14-16 

Alfalfa 8.9 8-13 

Tomato 7.6 7.6 

Corn 5.9 21-24 

Onion 4.3 11 

Rice 3.6 5.6-7.5 

Bean 3.6 8.0 



1/ From Maas, E.V., 1986. Salt Tolerance of Plants. In Applied 

~ Agricultural Research, Vol. 1, No. 1, pp. 12-26. 

y Salinity level at which a 50% yield reduction occurs. 

3/ Salinity level at which 50% of planted seeds emerge. 



6-51 



western San Joaquin Valley is summarized in Table 6.10, Many of the 
most sensitive crops are high value orchard crops which precludes 
their planting in most areas of the westside- 

In many cases salt sensitivity may result from single ion effects 
such as sodium (Na) or chloride (CI) rather than just the osmotic 
potential of the salt solution. These variable responses are 
discussed by Lauchli and Epstein (1985). 

Salt tolerant/ low water use desert plants including guayule/ 
jojoba, buffalo gourd, tepary bean, and guar have also been proposed 
as an alternative to the more traditional agricultural crops in the 
San Joaquin Valley (Mortensen et al . , (1981). At present there is 
little known about the agronomic potential of non-traditional crops 
in the San Joaquin Valley. However, if a profitable market can be 
found for a new crop and it is adaptable to the soil and climatic 
conditions of the area, then it will be grown. Such has been the case 
in California with avocado, kiwi, and pistachios. Obtaining a 
market for woody plants for fuel, oil seed crops (jojoba), rubber 
crops (guayule), food crops (buffalo gourd and tepary bean) and 
resins (guar) may prove much more difficult. In general, whatever 
crop is grown will face the same problem from increasing salinity in a 
closed system where salts are continually added from saline soil and 
geologic materials and moderately saline well water. 

6.5 SOIL AND SOBSORFACE DRAINAGE SYSTEM MANAGEMENT 

Reducing agricultural drainage flows or improving drainage water 
quality by managing subsurface drainage systems and soil physical, 
chemical, and microbiological properties has only received cursory 
attention by researchers. This is largely a result of the technical 
difficulties which arise in developing management practices that 
consider these characteristics. Further, when lands in the study 
area were developed, the approach used considered primarily 
economics with little regard for the soil and drainage 
characteristics which are presently at the forefront. The primary 
impact of soil properties on drainage flows relates to the spatial 
variability of these properties rather than the properties 
themselves. For example, improving the soil water intake rate by 
incorporating organic residues may not necessarily improve the field 
uniformity. It is this variability which can have a negative impact 
on subsurface drainage conditions particularly when using 
flood/furrow surface irrigation systems. With these systems the 
quantity of irrigation water required for an irrigation event is that 
amount needed to replenish the soil moisture supply in that part of 
the field with the slowest infiltration rate. As a result, other 
areas with more rapid permeability will receive excess irrigation 
water which will contribute to deep percolation losses. Attempts to 
reduce drainage flows by reducing spatial variability in soil 
properties have not been reported. In fact, management measures 
implemented to improve soil infiltration and permeability 
conditions have generally not been demonstrated to significantly 

6-52 



TABLE 6.10 
BORON TOLERANCE LIMITS FOR SELECTED AGRICULTURAL CROPS 



Crop 



Concentrat ion 
Threshold (ppm) 



Very Sensitive 
Lemon 



<0.5 



Sensitive 
Avocado 
Grapefruit 
Orange 
Apricot 
Peach 
Plum 

Fig/ Kadota 
Grape 
Walnut 
Onion 
Garl ic 
Wheat 
Sunflower 
Beans 

Moderately Sensitive 
Broccoli 
Chili pepper 
Carrot 
Potato 

Moderately Tolerant 
Lettuce 
Celery 
Barley 
Oats 
Corn 

Sweet Corn 
Muskmelon 
Cauliflower 

Tolerant 
Tomato 
Alfalfa 
Sugar Beets 

Very Tolerant 
Sorghum 
Cotton 
Asparagus 



y From Maas, E.V., 1986. Salt 

Agricultural Research, Vol 1., 



Tolerance 
No. 1, 



0. 


5- 


•0. 


75 


0. 


5- 


■0. 


75 


0. 


5- 


•0. 


75 


0. 


5- 


•0. 


75 


0. 


5- 


■0. 


75 


0. 


5- 


■0. 


75 


0. 


, 5- 


■0. 


75 


0. 


, 5- 


■0. 


75 


0. 


, 5- 


■0. 


75 


0. 


,5- 


-0. 


75 


0. 


,7f 


;-] 


..0 


0. 


,75-] 


..0 


0. 


,7E 


i-] 


..0 


0. 


,75-] 


..0 


1, 


.0- 


■2. 


.0 


1. 


,0- 


-2. 


.0 


1. 


, 0- 


■2. 


,0 


1. 


, 0- 


-2. 


,0 


2, 


.0- 


-4. 


,0 


2. 


. 0- 


-4. 


,0 


2. 


.0- 


-4. 


.0 


2, 


.0- 


-4. 


,0 


2, 


.0- 


-4. 


.0 


2, 


.0- 


-4. 


.0 


2, 


.0- 


-4. 


.0 


2, 


.0- 


-4. 


.0 


4 


.0- 


-6, 


.0 


4 


.0- 


-6, 


.0 


4 


.0- 


-6, 


.0 


6 


.0- 


-10.0 


6 


.0- 


-10.0 


10 


.0- 


-15.0 


o 


f ] 


Plants 


PP 


• 


12- 


-26. 



In Applied 



6-53 



improve soil uniformity. Thus, considering existing soil 

conditions in the study area, opportunities to improve the 

subsurface drainage condition by modifying existing soil 
characteristics probably do not exist. 

The most important consideration in evaluating existing soil 
conditions is their impact on irrigation and drainage system design 
and management. There may exist an opportunity to influence 
subsurface drainage conditions by implementing design and 
management approaches more consistent with prevailing soil 
characteristics. These design and management considerations 
ultimately will influence water conservation and irrigation system 
efficiency factors which were previously discussed. 

6.5.1 Soil Physical Properties 

Managing soil physical properties can influence potential 
subsurface drainage flow reductions. The rate of water percolation 
through the soil profile is controlled by the infiltration rate at 
the soil surface and the transmission properties of the most 
restrictive soil strata (hydraulic conductivity). Additionally, 
the soil moisture holding capacity and the water content at time of 
irrigation will determine whether a quantity of irrigation water 
infiltrating the soil will be retained in the crop root zone or pass 
beyond the root zone and thus be unavailable for evapotranspiration . 
Without consideration for management factors, the degree to which 
these soil properties affect subsurface drainage conditions is more 
a function of the spatial variability of these properties than of the 
properties themselves. 

Management practices that would provide the most uniform intake 
opportunity time in flood/furrow surface irrigation systems may be 
influenced by the high variability in soil infiltration rates in the 
irrigated field. Infiltration rates may vary naturally or may be 
affected by cultural operations. Natural factors that affect 
infiltration rates generally include rainfall rate and intensity, 
soil texture and structure, soil moisture content, organic matter 
content, soil temperature, and soil chemistry. Management factors 
that may affect infiltration rates generally include wheel traffic, 
cultivation, irrigation practices, soil amendments, and the 
chemicals in the irrigation water. Infiltration processes and 
factors controlling infiltration are more thoroughly discussed by 
Parr and Bertrand (1960), Henderson and Haise (1967), and LAWR - 
Cooperative Extension Joint Infiltration Committee (1984). 

The ability of soil to transmit water is determined by its hydraulic 
conductivity. Hydraulic conductivity is affected by the pore size 
distribution and pore interconnections, soil moisture content, and 
the chemistry of the soil water. Selected examples of physical 
features that may reduce hydraulic conductivity are the presence of a 
hardpan or plowpan and strata with fine soil texture (LAWR - 
Cooperative Extension Joint Infiltration Committee, 1984). 



6-54 



Several management practices can be employed to improve water 
infiltration rates and soil permeability (Henderson and Haise, 1967; 
and LAWR - Cooperative Extension Joint Infiltration Committee/ 
1984). However, these practices have not been shown to reduce field 
variability of the significant soil physical properties. This 
variability is the primary cause of excessive drainage from 
otherwise well managed surface irrigated fields. 

If management practices to improve infiltration rates and 
permeability can be selectively applied to known problem areas, then 
reduction in field variability may be possible. Those areas with 
poor infiltration rates that result from structural problems may be 
improved by deep tillage. It may be necessary to perform the deep 
tillage operation annually and the benefits may be short lived if 
soil strata have a high clay content- Incorporation of organic 
materials into the surface soil is another potential alternative. 
However, this approach has generally proven unsucccessf ul because of 
rapid combustion losses of organic matter that result from adverse 
climatic conditions. Soil organic matter content in the study area 
is well below one percent. When soil infiltration rates are reduced 
from the effect of high sodium levels, incorporation of soil 
amendments such as gypsum, may facilitate better water penetration. 
A more drastic and unacceptable approach where excessively high 
infiltration rates are a problem would be soil compaction or placing 
an impermeable barrier at some depth in the soil. This approach is 
not acceptable since it will severely impact crop root growth and the 
installation of an impermeable barrier would be prohibitively 
expensive. A discussion of management practices is presented by the 
LAWR - Cooperative Extension Joint Infiltration Committee (1984) and 
Unger and Stewart (1983). 

Another important soil physical property is the soil moisture 
holding capacity. The moisture holding capacity is largely a 
function of soil texture with finer textured soils having higher 
moisture holding capacity than coarse textured soils. The moisture 
holding capacity largely determines whether a quantity of irrigation 
water infiltrating the soil will be retained in the crop root zone or 
pass beyond the root zone and contribute to deep percolation. The 
moisture holding capacity is an important factor in selecting and 
operating irrigation systems since it can have a significant 
negative impact on achieving acceptable irrigation efficiency. 
Methods to increase the soil moisture holding capacity are discussed 
by Unger and Stewart (1983). The most important method that can be 
used in the San Joaquin Valley is ripping to increase the effective 
rooting depth. This technique is used to break up soil strata of 
high clay content or pans. In general, soil moisture holding 
properties are an inherent soil feature that is not easily modified 
short of drastic physical alteration of the soil profile. Thus, 
management practices that may be economically implemented to create 
more spatially uniform soil moisture holding characteristics over 
the field are not generally available. 



6-55 



6.5.2 Soil/Irrigation Water Management 

Even though the modification of existing soil conditions is 
considered uneconomical or impractical, irrigation system design 
and management alternatives can often largely offset the potential 
negative impacts. Implementing sprinkler or drip irrigation 
techniques can largely address infiltration problems on fields with 
variable intake rates. The cost of installing these facilities is 
high when compared to flood/furrow techniques. Further, sprinkler 
systems are not well suited to soils with intake rates less than about 
0.2 inches per hour because of design, equipment and management 
limitations. These soils are usually flood/furrow irrigated 
because of this limitation. The modification of existing 
flood/furrow irrigated fields by changing field configuration, 
length of run, slope, and inflow rate appears to be a feasible 
alternative for improving the irrigation efficiency of existing 
operations. This approach, coupled with improved management 
techniques such as surge flow and tailwater return, could increase 
irrigation efficiency to levels equivalent to more expensive 
automated systems. The management requirements will be more 
intensive to obtain these efficiencies. 

The available moisture holding capacity affects the ability to 
obtain acceptable irrigation efficiencies by influencing frequency 
and duration of irrigation. This factor evaluated in conjunction 
with infiltration rate is the major consideration in irrigation 
system design and operation. For example, the infiltration rate 
dictates the amount of time needed to intake a specific water depth 
while the available moisture holding capacity governs that depth of 
water needed. Field slope, length of run, and flow rate are 
calculated based on these factors. As previously stated, it is 
generally not practical to change the moisture holding capacity; 
however, management can influence irrigation scheduling based on 
allowable moisture depletions between irrigations. Irrigation 
systems are typically designed to cycle through the field so that 
irrigations are timed for application when the soil reaches this 
depletion. Irrigating at higher allowable depletion will generally 
cause moisture induced stress and yield loss while more frequent 
irrigations result in reduced efficiency and higher deep percolation 
losses. Coarser textured soils also require more frequent 
irrigation because of their lower moisture holding capacity. The 
important aspects of irrigation scheduling were previously 
discussed . 

The impact of these soil factors can largely be addressed by proper 
irrigation system design and operation. Other management factors 
such as mulching, tillage and night irrigation, which may reduce 
evaporation losses, are generally not significant factors for 
improving subsurface drainage conditions in the study area. 
Subsurface drip irrigation may be an alternative by which 
evaporative losses can be reduced. Since this system is buried and 



6-56 



water is applied directly in the root zone area, soil surface 
evaporation losses are significantly reduced. It appears necessary 
to reevaluate ET concepts in relation to this alternative since total 
water requirements may be reduced. Presently, research needs to be 
performed to evaluate the magnitude of the potential benefit. 

6.5.3 Microbiological Factors 

The primary beneficial influence of soil organisms on soil physical 
properties is that of binding soil particles into aggregates. The 
formation of soil aggregates promotes increased infiltration rates. 
Microbial activity and aggregate formation are promoted by additions 
of organic materials to the soil to act as a food source. As 
previously stated, however, increasing the soil infiltration rate 
without also reducing the field infiltration rate variability is 
probably ineffective in reducing deep percolation regardless of the 
irrigation management applied. 

The effect of soil organisms on drainage water quality may be 
significant. Many elements occur in several oxidation states in the 
natural soil and water environment. Their transformation from one 
oxidation state to another is mediated by soil organisms. The 
effects of microorganisms are exhibited in flooded soils where iron 
and manganese are reduced to more soluble forms and where sulfate- 
sulfur is reduced to the insoluble sulfide form. Several 
potentially toxic inorganic elements in soils including mercury, 
arsenic, and selenium are also subject to changes in oxidation state 
mediated by microbial organisms. Methylmercury may be formed in 
soils and waters from mercury by microorganisms regardless of the 
oxidation state of the environment. Selenium occurs naturally in 
soils in primarily the selenite and selenate forms. Under alkaline 
soil conditions, the more soluble selenate form prevails while under 
acid conditions, the more insoluble selenite form is predominant. 
It has been shown that soil microorganism can mediate selenium 
transformations. In anaerobic environments selenate may be reduced 
to selenite or to elemental selenium. Formation of dimethyl- 
selenide has also been observed. Arsenic undergoes many of the same 
chemical reactions as selenium. It also occurs naturally in soils 
in the arsenate and arsenite forms and is subject to microbial 
transformation. 

Although the type of microbiological organisms cannot easily be 
controlled, in some cases the environment can be. In the presence of 
a reducing environment and an adequate carbon supply, a reduction of 
selenium to a more insoluble and, thus, less mobile form may be 
realized. In soils these reactions would be very slow and entail a 
drastic change in soil chemical properties. The treatment of 
drainage waters is more easily managed. It has been suggested that 
introduction of methanol into the drainage system will effect a 
transformation of selenate to the more insoluble selenite form which 
would then be more easily removed by precipitation (JM Lord, Inc. 
1985). Methanol can be used as a carbon source under anaerobic 



6-57 



conditions to support microorganisms which contribute to the 
reduction of selenate. However/ the treatment may be ineffective 
due to the slow rate of reduction of selenium in the natural 
environment. The most effective use of microorganisms may be in the 
treatment of drainage waters under well controlled conditions in a 
specially designed treatment facility. 

6.5.4 Soil Amendments 

The addition of soil amendments may indirectly reduce deep 
percolation losses by improving soil physical properties such that 
soil infiltration rates are more uniform over the field. This 
facilitates improved irrigation efficiency. Soil amendments that 
may be used include organic materials and mulches. However; the 
benefit from these materials will be short lived because of 
prevailing soil and climatic conditions. Where soil infiltration 
problems occur as the result of the presence of sodium, amendments 
such as gypsum may be required. A side effect of adding gypsum is 
that the added salts may contribute to the overall soil and drainage 
water salinity problem. Evidence is not available and it is 
unlikely that soil amendment applications will increase irrigation 
uni f ormity . 

6.5.5 On-Farm Subsurface Drainage Design 

Subsurface drainage systems were installed in the San Joaquin Valley 
to reduce the elevation of high water tables caused by a combination 
of irrigation and restrictive soil profile conditions. Their 
installation was predicated on the assumption that drainage waters 
would be recycled back into the distribution system, into nearby 
waterways, into deeper groundwater aquifers or to the Sacramento-San 
Joaquin Delta. 

Current drainage design practices call for maintaining the water 
table at a level below the maximum crop rooting depth and for 
maintaining a salt balance in the soil profile below the salt 
tolerance level of the most sensitive crop grown. The salt balance 
would be maintained by establishing a drainage flow to water 
application ratio, i.e., leaching fraction, sufficient to maintain 
the steady state soil salinity at a designated concentration. With 
current limitations on allowable drainage discharges, it is 
necessary to re-evaluate the design criteria. Recent research has 
demonstrated that cotton and some other row crops in the San Joaquin 
Valley can be grown successfully in the presence of a shallow saline 
water table. It was also shown that this water table could 
contribute up to 50% of the crop water requirement (Wallender et al., 
1979; Kite and Hanson, 1984; Grimes et al., 1984; and Ayars and 
Shoneman, 1984). 

Given these considerations, drainage design factors must be 
reconsidered to obtain an optimum water table depth in order to 
minimize drainage flows while maintaining crop production. 



6-58 



Drainage design must also be closely integrated with irrigation 
design and management objectives to achieve the desired results. 

Current drainage design practices in California result in drain 
depths of about 8 feet in order to assure a midpoint water table depth 
sufficient to meet design requirements. The depth is selected to 
assure that capillary rise of water into the root zone is minimized. 
In order to reduce drainage flows, and increase crop use of drainage 
water, it is necessary to design subsurface drainage systems with 
either a wider drain spacing or a shallower drain depth. Where tile 
drainage systems are already in place, alternate collector drains 
could be permanently plugged or external controls placed on drainage 
flows in order to maintain a higher water table. Two drainage design 
computer models which consider the contribution of the shallow water 
table as a component of ET as well as drainage water salinity are 
described by Ayars and McWhorter (1985). Cost factors for 
installing subsurface drains are discussed by Fitz et al. (1980) with 
respect to a feasibility study of installing drains in the Panoche 
Water District in Western Fresno County. 

Drainage system design can be modified to reduce subsurface drainage 
flow by allowing the water table to rise to levels where these waters 
can partially contribute to the crop water requirement. This 
requires either shallower drainage design depth or wider drain 
spacing. Another method to control water table depth is to control 
the discharge by blocking drains at selected times. These 
alternatives for drainage design and management must be closely 
integrated with surface irrigation practices to achieve maximum use 
of the shallow groundwater while minimizing drainage flows. 
Adequate irrigation water must also be applied to provide sufficient 
leaching to maintain soil salinity at an acceptable level for the 
crop grown. This management alternative appears very feasible 
especially for areas requiring future drainage since it will both 
reduce drainage flows and decrease subsurface drainage facility 
cost . 

6.6 ON-FARM TREATMENT/STORAGE OF DRAINAGE WATERS 

Evaporation and storage ponds provide an alternative for dealing 
with excess drainage waters. Methods for managing the ponds as well 
as removal of toxic materials by chemical or biological processes are 
discussed in the following section. 

6.6.1 Storage/Evaporation Ponds 

In the absence of off-farm facilities for removing drainage waters 
from the farm, it may be necessary to build storage and/or 
evaporation ponds to hold these waters either for reuse, treatment, 
or disposal. Small storage facilities are already in use for 
recycling tailwaters on some farms. However, the extent to which 
storage facilities for only subsurface drainage waters have been 
built is unknown. Currently, subsurface drainage waters are most 

6-59 



likely recycled from a sump or drainage ditch. 

The cost of building evaporation ponds may exceed that of temporary 
storage pondS/ especially if appreciable concentrations of 
potentially toxic elements are likely to concentrate in the sediment 
or brine. These costs may escalate because of permit requirements 
from the Regional Water Quality Control Board needed to operate an 
evaporation pond. Further; eventually the water quality of the pond 
may exceed limits defined for a hazardous waste facility. Short of 
this/ a hazard may still be posed to wildlife from ingesting plant and 
animal materials growing in the pond environment. 

Annualized construction costs for a simple unlined pond were 
estimated to be about $555 per acre by Knapp et al. (unpublished) 
adjusted for the year 1983 based on estimates of Summers (1983). 
Knapp et al. also estimated an annualized salt removal cost of $40 per 
ton based on information supplied by C. Stroh (USER/ 1985). The cost 
of building a Class II pond to meet the requirements specified by 
Subchapter 15 of the California Administrative Code was estimated to 
be between $20,000 and $50,000 per acre by Larry Glandon of the Water 
Quality Control Board (WQCB), Central Valley Region. The WQCB 
issues permits to build and operate agricultural waste discharge 
storage facilities and is exempting the application of the 
provisions of Subchapter 15 requirements for Class II ponds if the 
pond is judged to meet the water quality requirements specified for 
the Tulare Lake Basin Plan. Estimated costs of Class I ponds range 
from $180,000 to $200,000 per acre. 

The major chemical reactions expected in evaporation ponds in the San 
Joaquin Valley are discussed by Tanji et al. (1985). Evaporites are 
expected to be similar to those formed during evaporation of 
seawater. Tanji et al. (1985) estimated that if 1400 mg/1 TDS water 
is discharged to the ponds that 10 inches of salt would build up over 
a 20 year period. The increasing concentration of selenium in 
evaporation ponds would be expected in time since it occurs in a form 
(selenate) that is not easily precipitated or adsorbed. 

The size of the evaporation pond will depend on the expected average 
annual and monthly distribution of drainage flow into the pond, the 
evaporation rate, and possibly the seepage rate. The total amount 
of evaporation from the pond will depend primarily on the surface 
area and the location in the study area. The evaporation rate can 
vary from 3.5 to 5 acre-feet/year. Therefore, if the average depth 
of drainage water over the area of a cropped field is one foot, and 
the average annual evaporation rate is 5 acre-feet, then the 
evaporation pond must have a surface area of 20 percent of the cropped 
area. If irrigation efficiency is increased such that the average 
depth of drainage water is only one-half foot, then the required pond 
surface area need only be 10 percent of the area of the cropped field. 
The area considered addresses only the pond surface area and does not 
include area needed for dikes, perimeter roads or other facilities. 



6-60 



Costs incurred from increased irrigation efficiency would be the 
implementation cost of improved management practices or reduced 
yields occurring from insufficient water application resulting from 
variability in soil physical properties and non-uniformity of 
irrigation applications. An additional effect of reduced drainage 
is an increased salt load in the soil profile which may result in 
planting more salt tolerant; but less profitable crops. These 
factors were considered by Knapp et al . (unpublished) in an analysis 
of on-farm management alternatives when off-farm export of drainage 
water is not allowed or if allowed, then at a significant price. 

6.6.2 Reduction and/or Precipitation of Selenate 

The natural form of selenium in highly oxidized alkaline soils and 
waters is the soluble selenate anion. This form may be quite mobile. 
The selenite form of selenium which is the common form in either acid 
or alkaline reduced environments is readily adsorbed onto iron oxide 
fractions of soils and is therefore quite immobile. With this 
understanding of the chemistry, proposals have been made to 
immobilize selenium in the soil or subsurface drainage lines by 
creating a reducing environment. There are three requirements to 
create a reducing environment: 1) absence of oxygen; 2) the 
presence of reducing bacteria; and 3) a carbon source (food) for the 
bacteria. If one of these requirements is not satisfied, then the 
reduction of oxidized elements may be considerably slowed. 
Suggestions to flood the soil by temporarily blocking drains and 
injecting methanol (carbon source) into the soil or drain lines were 
made by JM Lord, Inc. In principle this is a logical approach 
although JM Lord, Inc. noted that permanent plugging of drains may 
become a problem. Reference to the industrial chemical reduction of 
selenate to selenite, however, also reveals that this reaction is 
very slow in an alkaline environment (Jennings and Yannopoulos, 
1974) such as that occurring in the study area. 

6.6.3 Bio-Accumulation 

Using plants to absorb potentially toxic constituents from soil and 
water has not been practiced to any significant extent in California 
outside of sewage treatment facilities. Evidence for the 
accumulation of selenium by plants dates back to about 1939 (Beath, 
1939). In fact, seleniferous soils were mapped based on the 
distribution of species of Astragalus (vetch) in the Rocky Mountain 
states. Selenium accumulator plants were also used to locate 
uranium ores due to the association of selenium with uranium on the 
Colorado Plateau (Rose et al., 1979). In addition to Astragalus, 
other primary indicators were found to be species of Haplopappus and 
Stanleya. Secondary accumulators included species of Aster, 
Atriplex, Castilleja, Grayia, Grindelia, Gutierrezia, Machaer- 
anthera, and Mentzelia. Primary indicators may contain from 1,000 
to 10,000 ppm selenium (air dry basis) and secondary accumulators, 
several hundred ppm. Selenium levels of wheat and corn grown in 
seleniferous areas were only 30 ppm (Smith and Westfall, 1937). 



6-61 



Selenium contents of several accumulator plants and food crops in 
seleniferous soils are summarized in Table 6.11. 

TABLE 6.11 
SELENIUM CONCENTRATIONS IN PLANTS GROWN 
ON SELENIFEROUS SOILS 



Plant Se(ppm) 



\r 



Primary Accumulators: 



Astragalus 1,000 - 15,000 

Zylorhiza 1,400 - 3,490 

Stanleya 1,200 - 2,490 

Oonoposis 1,400 - 4,800 

1/ 
Secondary Accumulators: 

Grindelia 38 

Atriplex 50 

Gutierrezia 60 

Astor 70 

2/ 

Food Crops: 

Wheat 30 

Corn 30 

Barley 17 

Onions 18 

Tomatoes 1.2 



_!/ Brown et al. (1983), p. 290 
y Trelease and Beath (1949) 

Based on the total amount of selenium absorbed and translocated to 
the aerial parts of the best selenium accumulators, there could be a 
significant uptake of selenium into selenium accumulator plants 
given sufficient production of above ground matter. Cropping 
alfalfa with vetch could be such a management alternative. The 
forage could not be used directly itself for consumption by cattle 
but could be mixed with low selenium alfalfa as pellets for 
distribution to low dietary selenium areas. This approach may prove 
to be a problem in that markets for this type of product may be very 
small or non-existent. In addition, legal implications should be 
considered because of potential liability that could result if 
toxicity occurred to animals consuming the forage. Consumption of 
this forage in the field by rodents which are prey to avian predators 

6-62 



may also be a problem. The production of noxious dimethyl 
diselenide gases by selenium accumulators with high concentrations 
of selenium may partially alleviate this problem. The actual effect 
of a selenium accumulator crop on drainage water quality can not be 
determined; however, this approach does not address the other toxic 
constituents or salinity and as a result is probably not a viable 
alternative . 

Using accumulator plants in ponds has also been suggested. In fact, 
several plants found in marshes in the San Joaquin Valley have been 
shown to concentrate selenium in their tissues. Several 
individuals (see Section 5) have suggested using water hyacinths to 
remove pollutants from pond waters. This is a practice that has been 
tried in regions of the country with non-saline waters for the uptake 
of trace metals. Its application to highly saline waters with high 
boron concentration for the removal of nonmetalic trace elements 
such as selenium has not been demonstrated. The use of any 
accumulator plant in a pond would still present a problem in the 
wildlife food chain unless exclusion of wildlife was provided. 
Currently there appears to be no satisfactory method for excluding 
wildlife . 

6.7 ECONOMIC/INSTITUTIONAL CONSIDERATIONS 

The implementation of recommended on-farm management alternatives 
will probably reduce farm net profit. As a result, the 
implementation plan which includes measures to improve on-farm 
management in the study area will need a significant capital 
investment and require economic and/or institutional incentives. 
These incentives can take many forms. For example, growers could be 
charged for irrigation water on a sliding scale with rates increasing 
with increased water use; or excess irrigation water saved by the 
implementation of water conservation measures could be marketed to 
other users with that grower reimbursed for his water conservation 
measures from monies obtained from the sale of the water. Another 
option could be to charge a grower for his discharged drainage water. 
This requires the local government to successfully allocate these 
costs or associated revenues to the proper farmer. Developing an 
approach to charge the upslope contributor would be difficult 
because of the need to accurately determine his discharged drainage 
water. The technology to determine these drainage volumes has not 
been developed. 

Institutional assistance appears necessary to provide the economic 
and financial support. Institutional constraints which may need to 
be addressed include factors such as water rights laws, water 
allocation policies, water quality standards, lending policies of 
financial institutions, grant monies for on-farm management 
modifications, allocation of treatment costs, agricultural drainage 
management by government institutions, existing water contracts, 
and available labor. These factors will ultimately need to be 
addressed in order to efficiently and economically implement 



6-63 



improvements which will facilitate reduced subsurface drainage 
flows or improved subsurface drainage water quality. In addition to 
these constraints which must be considered for implementation, 
existing economic and institutional considerations currently in 
place must be addressed in the evaluation of many of the proposed on- 
farm agricultural management alternatives. Thus, the economic and 
institutional considerations include not only existing factors 
which may impede the development of appropriate on-farm management 
alternatives/ but also those which must be addressed in order to 
offer adequate incentives to guarantee grower participation in the 
program. 

6.7.1 Irrigation Water Delivery 

Improving the irrigation efficiency of on-farm application systems 
is largely dependent on the flexibility of the farm water delivery 
system. To maximize irrigation efficiency, irrigation water must 
be delivered at the time needed with the proper flow rate for the 
required duration of the irrigation event. Older irrigation 
systems developed when water was more plentiful are generally the 
least efficient. When these older irrigation systems were 
developed allowances were made for excess irrigation water which was 
provided to reduce labor costs and the risk of crop water stress. JM 
Lord, Inc. (1981), in an evaluation of water delivery system 
flexibility in California noted that water districts are severely 
constrained in their ability to provide a flexible delivery schedule 
by the water purveyor, the DWR or USER, to the district. Limitations 
in water delivery systems and recommendations for their improvement 
to facilitate better on-farm irrigation scheduling are discussed by 
Repogle and Merriam (1980). 

Recently, the water delivery year was changed from January 1- 
December 31 to March 1-February 28. The purpose of this change was 
to encourage irrigators to conserve irrigation water by reducing 
pre-irrigation amounts by the volume of effective precipitation. 
The impact of this change remains to be seen. However, it is likely 
to have minimal impact on the magnitude of irrigation water 
applications since most pre-irrigations are made in December and 
January before winter precipitation is known. Thus growers are 
likely to apply their remaining water allotment as a guarantee of 
obtaining adequate soil moisture reserves. Therefore, the 
modification of the water delivery year, although a step in the right 
direction, will likely not have any noticeable impact on reducing 
subsurface drainage flows. 

6.7.2 Irrigation Water Pricing 

Increasing the price of irrigation water has been considered as an 
institutional incentive which may improve on-farm irrigation 
efficiency and reduce deep percolation losses to the shallow 
groundwater table. In California water districts with the highest 
priced irrigation water are those which generally contain the most 



6-64 



efficient irrigators. For example, San Diego County has the most 
expensive agricultural water. Farmers in that area have responded 
by installing some of the most efficient irrigation systems 
operating in California. In the San Joaquin Valley, irrigation 
water supplied to the study area has historically been inexpensive. 
Thus, when agricultural lands were developed, the emphasis was 
placed on minimizing initial development costs, often at the expense 
of efficient irrigation. 

In general. Federal CVP waters are inexpensive. The price presently 
under contract is normally fixed with water districts for forty-year 
periods without interest charged on the capital expenditure for 
project development. Because of these contractual obligations to 
water agencies, increasing the price of irrigation water is not 
possible until the time of contract renewal. The contract renewal 
process will not begin until about 1989 in the study area. Water 
costs for SWP waters, however, are based on the actual amortized cost 
of the system. 

Increasing the costs of irrigation water will be resisted at the farm 
level, especially by irrigators with inefficient systems. Even 
though increasing the cost of irrigation water will act to conserve 
water and reduce subsurface drainage flows, the additional 
irrigation costs may be enough to make the farming operation 
unprofitable because of the increased irrigation water costs or the 
increased management costs necessary to conserve water. Another 
possibility is that it may become more economical to increase 
groundwater pumpage from the deeper non-saline aquifers such that 
net reductions in applied water would not be achieved. Further, in 
those districts where the price of water is very low, a large increase 
in the water price may be required to induce increased irrigation 
efficiency since water costs constitute a very low percentage of the 
total farming cost. 

Increasing the price of irrigation water will not necessarily result 
in improved irrigation efficiency. Instead, crops with lower water 
requirements may be planted. Thus, a savings of irrigation water 
will be achieved, but deep percolation losses to the shallow 
groundwater table may be equivalent if viewed on a percentage basis. 
One potential alternative to dealing with this problem is to price 
water on an incremental basis. Water could be sold to an irrigator 
based on the crop grown and the expected annual ET with an allocation 
included for a fixed allowable irrigation efficiency. This water 
would be sold to the grower at existing water rates. If the grower 
were an inefficient irrigator and required water in addition to his 
allocation, then he would be charged at an increasing incremental 
rate. Regulations would need to be implemented which would restrict 
groundwater pumpage during normal water supply years. 



6-65 



6.7.3 Drainage Effluent Pricing 

Levying a charge on drainage water discharges is another economic 
incentive that may be applied for purposes of reducing drainage 
flows. Although logically the fairest method for attributing the 
cost of treatment for drainage discharged to the source/ it is 
technically very difficult to identify the source of drainage 
waters. Subsurface drainage waters are discharged as both point 
sources from subsurface drainage collectors into drainage canals and 
as seepage. In addition, groundwaters are not static but move in 
response to hydrologic gradients at a rate dependent on the slope of 
the water table and the hydraulic conductivity of the porous aquifer. 
Therefore, it would be very difficult to determine the source of the 
drainage water from a field whose groundwaters may be continuous with 
surrounding fields. 

Methodology is available to estimate on-farm deep percolation losses 
based on using on-farm water budget approaches. This methodology 
would facilitate the relatively accurate estimate of unit deep 
percolation losses. These estimates could then be expanded based on 
the cropping pattern and acreage to estimate deep percolation losses 
occurring at a particular field or farm. There would be annual 
expenses involved in performing the survey to determine the cropping 
pattern and acreage. Further, the accuracy of estimating applied 
water will vary from district to district and farm to farm. This 
approach contains inherent inaccuracies which would lead to 
miscalculations of deep percolation losses in many areas. For 
example, water deliveries to the farm headgate may not be precisely 
measured in certain irrigation districts. Irrigation districts 
with a pipeline water conveyance system would be the easiest to 
monitor. Additional difficulties would arise if the irrigator is 
also using riparian or groundwater supplies. Developing a system 
which could be used to charge for drainage water discharged does not 
appear to be a viable approach for providing economic incentives or 
disincentives needed to reduce subsurface drainage flows. 

A potential approach for dealing with on-farm drainage costs is the 
expansion of existing or the creation of new local government 
agencies such as drainage districts. These districts could be 
formed based on the identification of drainage problem areas. It is 
anticipated that the drainage problem area would include not only 
those lands which currently have a drainage problem, but also lands 
upslope which could be contributing to the problem. The creation of 
these districts would allow the allocation of drainage and salt 
management costs for repayment by all those who are contributing to 
the problem. This approach could also allow for the payment of 
treatment costs which would be incurred in the removal of 
contaminants prior to water reuse and/or disposal. This approach 
would again facilitate the allocation of costs to those who are 
creating the problem. 



6-66 



5.7.4 Removing Drainage Problem Lands from Production 

Removing drainage problem lands from agricultural production is an 
institutional alternative which may act to reduce but not eliminate 
the subsurface drainage discharge problem. In the western San 
Joaquin Valley where rainfall is insufficient to percolate to the 
groundwater in most years/ this option would almost eliminate deep 
percolation losses. This particular option will/ however, have a 
drastic economic impact on farms and communities associated with the 
lands removed from production. Investments associated with land/ 
equipment/ and other facilities would not be recoverable. Further/ 
a significant economic hardship would be placed on communities 
surrounding these agricultural lands. Should the Federal and State 
government pursue this alternative/ a very careful economic analysis 
is required to evaluate the annual impact/ not only on lands removed 
from production/ but also on lost income to those involved in the 
production and marketing of agricultural commodities which would 
have been produced from those lands. AlsO/ secondary economic 
impacts must be considered for others living in the agricultural 
community. The alternative uses for water not used on lands removed 
from production should be evaluated in regard to potential 
beneficial uses as an element of the analysis. 

6.7.5 Water Quality Monitoring Systems 

The implementation of a water quality and quantity monitoring system 
for agricultural subsurface drainage flows would facilitate 
decisions regarding the reuse or discharge of these waters. 
Monitoring would need to be performed at the farm drainage outlet or 
in some disposal collection facility. During periods when 
subsurface drainage water quality was acceptable/ these waters could 
be blended with fresh irrigation water supplies for reapplication . 
Presently/ few growers in the study area are monitoring tailwater or 
subsurface drainage water quality. Monitoring considerations 
should also address the need to measure irrigation flows to the farm 
headgate/f ield to facilitate more accurate irrigation applications. 
This monitoring is needed to improve management capability needed to 
optimize irrigation efficiency. 

6.7.6 Water Marketing 

The concept of marketing excess irrigation waters was previously 
mentioned. With this approach/ irrigators who become more 
efficient and are able to conserve their water supply/ could then 
market the conserved water to other users. The other users could 
consist of other irrigators in the district or M&I users. A multitude 
of constraints exist which presently make water marketing 
sufficiently restrictive to prevent natural economic forces from 
providing strong incentives for the farmer to become more efficient. 
USBR policy dictates that a profit cannot result from the sale or 
transfer or water allocated to the existing CVP contractor. The 
price of transferred water would be limited to the price paid to the 

6-67 



USER/ plus administrative and conveyance system costs associated 
with the transfer. The remaining CVP yield would be used to satisfy 
existing demands before approval to transfer water already under 
contract . 

The State Water Resources Control Board water rights permit does not 
allow CVP water to be delivered to the SWP service area. The SWRCB 
must be petitioned to modify current CVP water right permits to 
expand the consolidated place of use of CVP water to include the 
entire SWP service area. Further/ any water sale must comply with 
the Reclamation Reform Act and the restriction of the Act to sell to 
agricultural lands must be clarified. 

The CVP water contracts will begin to be renegotiated by 1989. If 
water is presently under-utilized; then the extended contract will 
include a reduced volume and thereby reduce the incentive for any 
individual water user to resell a portion of his water. Other CVP 
water customers will compete for this and any other water which 
becomes excess to existing water users. The objective of allowing 
the agricultural water user to sell his water is to provide an 
incentive for him to increase his water application efficiency. 
This may be negated by allowing him to increase his groundwater 
pumping capability; thus providing a substitution for the CVP water 
and not satisfying the need to reduce the drainage volume by reducing 
water application and water losses. If water sales are allowed; the 
SWRCB should address this issue and provide incentives which would 
reduce groundwater pumping. These incentives should stop short of 
groundwater basin adjudication. The Sacramento Valley in-basin 
user would also compete for any available water as a result of any 
proposed conservation methods related to San Joaquin Valley 
irrigated agriculture. Principally; those interested groups 
associated with increasing the outflows from the Delta and flushing 
the San Francisco Bay system would expect to obtain a share of water 
relinquished by agriculture in the San Joaquin Valley. This would 
likely result in a political struggle to secure permission for the 
resale option. 

The State of California Area of Origin Water Rights Principle may 
restrict the flexibility of the USER where the water districts 
receive CVP water for resale to other water export areas. A 
clarification of this issue is needed from the SWRCB. The effort 
required to allow the sale of water to enter the market place would be 
significant. There would be considerable expense involved in the 
legal; institutional; and political phase needed to develop an 
approach to allow the sale of CVP water to a third party. Further; 
any resale of CVP water has the potential to alter the social and 
economic conditions of the local communities; and they could become 
key players in resisting the resale program. 

An adequate EIS/EIR would be required to evaluate the impact of 
developing the water market capability. This document would become 
the vehicle for focusing appropriate public attention to the issue. 



6-68 



One of the criteria for formulating a water resale plan is that all 
parties feel that they are better off/ or at least no worse off, as a 
result of its implementation. Further work is needed to determine 
the feasibility of developing a third-party water market. 
Simplistically / it would seem that the evaluation of this approach 
would include the identification of: 1) the preferred reallocation 
in which participants are better off or at least no worse off; 2) 
constraints which prevent the water market sales; and 3) proposed 
methods of overcoming existing or anticipated constraints- 

The water marketing approach appears to offer strong incentives to 
the development of a water conservation plan since monies obtained 
from water sales could be reinvested to improve on-farm water 
conservation practices. This approach, although presently 
constrained by a myriad of institutional and social problems, should 
be further evaluated to determine its merit. 



6-69 



SECTION 7 
EVALUATION OF ALTERNATIVE MANAGEMENT PRACTICES 

7.1 EVALUATION CRITERIA 

The technical aspects of the alternative agricultural management 
practices were discussed in Section 6. Section 7 addresses and 
evaluates the alternative agricultural management practices in 
relation to their implementation as affected by individual farmer 
decisions. A farmer maximizes his operation under his conditions 
applying rational decisions and will not change his operation until 
he has reason. The reason for change may be based on many factors but 
in the absence of institutional pressure/ technical and economic 
considerations are probably the most important. A farmer must 
perceive that he will benefit as a result of the change to provide the 
incentive to take the risk. It would be unlikely that upslope 
farmers would change their operations since they have no incentive or 
reason to do so. To give upslope farmers an incentive to improve 
their operations and minimize contributions to the drainage problem, 
it may be necessary to provide an economic incentive, disincentive, 
or regulation. 

Management practices are evaluated in five categories: 1) 
technical, 2) economic, 3) legal/institutional, 4) environmental, 
and 5) social. These categories were judged to represent the range 
of considerations that must be made prior to implementing a 
management practice. In each category, matrix components 
(criteria) representing specific factors that must be considered in 
making a management decision were defined and used as a basis for 
evaluation (see Table 7.1). 

7.1.1 Technical Feasibility 

Most identified management practices have been shown to be 
technologically feasible. However, the technical considerations 
that need to be made prior to implementation need further evaluation. 
This evaluation must be made with the assumption that the management 
alternative is the most appropriate practice for the soil, crop, and 
land topography for which it is to be implemented. Several criteria 
were therefore established to compare the suitability of these 
practices in a farming environment and included the following: 

o Effectiveness of technical solution. 

o Availability of technology. 

o Ease of implementation. 

o Ease of operation/maintenance. 

o Time needed for implementation. 

7- 1 



TABLE 7.1 
EVALUATION CRITERIA FOR ON-FARM MANAGEMENT ALTERNATIVES 



Criteria 



1. Technical 

a. Effectiveness of Technology 

b. Availability of Technology 

c. Ease of Implementation 

d. Ease of Operation and Maintenance 

e. Time Needed for Implementation 

2. Economic 

a. Life Expectancy 

b. Fixed Costs 

c. Variable Costs 

3. Environmental 

a. Soil Resources 

b. Groundwater Resources 

c. Surface Water Resources 

d. Biological Resource 

e. Agricultural Land Resource 

4. Legal/Institutional 

a. Federal/State Regulations 

b. District Contract Regulations 

c. Water Marketing and Pricing Policies 

d. Pond Design Requirements 

5. Social 

a. Human Resources 

b. Social Services 



7- 2 



7.1.2 Economic Feasibility 

The economics of implementing a new practice are the most important 
criteria from a grower's perspective. A farm must be profitable if 
it is to remain in business. Therefore/ the effect of new management 
practices on long term profitability needs to be seriously 
considered. Many sets of economic data exist for crop production 
costs; however, since most economic data on the costs of alternative 
management practices are generally out of date or not readily 
available, it is only with difficulty that economic criteria can be 
evaluated. Further, the atypical nature of farming enterprises 
makes the application of the available economic data to the project 
area relatively meaningless. Economic criteria include the 
following : 

o Equipment costs (fixed costs) 

o Operating and maintenance costs (variable costs). 

o Life expectancy. 

o Incentives. 

Equipment costs are the annualized cost of purchasing and installing 
a management technology or practice. This is a direct cost that must 
be paid regardless of whether the practice is effective. These 
fixed costs must be paid annually at the same level regardless of the 
amount of use. Also included are costs for depreciation, repayment 
of loans, and interest. 

Operational costs include those for operation, maintenance, energy, 
management, and labor. The magnitude of these variable costs is 
dependent on the amount of annual use. 

Life expectancy is primarily considered with respect to estimating 
annualized installation costs as related to the expected useful 
life. Life expectancies may vary from a year for 
irrigation systems to 25 years or more for piped 
facilities. 



some drip 
conveyance 



Certain incentives may be provided to reduce the costs of installing, 
operating, and maintaining a facility or management practice. 
These may range from financial credits for using an irrigation 
scheduling service to energy credits for pumping water during off 
peak hours. Penalties for continuing inefficient farm management 
procedures may also affect the decision to implement management 
alternatives. Incentives are generally established by institutions 
which may not provide predictable reliability needed for long term 
economic planning. 



7- 3 



7.1.3 Environmental 

The environmental problems encountered in the project area result 
from the lack of effective water management practices. These 
problems have created an acute public awareness to the degradation of 
the local environment. Therefore/ it is imperative to evaluate the 
environmental impact of each on-farm management alternative. 

The environmental evaluation criteria consider the impact of an on- 
farm management practice on the following resources: 

o Soil 

o Groundwater 

o Surface water 

o Biological 

o Agricultural Land 

The soil resource is directly influenced by many on-farm management 
practices. Increasing irrigation efficiency may result in 
increasing salinization of the soil profile. In general, changes in 
soil physical/ chemical/ and biological properties with respect to 
crop production and other uses are criteria used to evaluate the 
effects of an on-farm management practice on the soil resource. 

Groundwater resources/ which include both shallow and deep water/ 
are potentially influenced by certain on-farm practices. Potential 
changes in depth to water table/ water quality/ and rates of 
groundwater flow resulting from implementation of a practice are 
criteria on which to evaluate the effects on the groundwater 
resource. For instance/ increasing salinity of the groundwater 
will affect its suitability for irrigation/ fish and wildlife/ 
livestock/ manufacturing and industrial/ and domestic uses. 

Surface water resources can potentially be altered by point and non- 
point pollution resulting from improper or misused agricultural 
practices. Changes in surface water quality and quantity should be 
considered when evaluating the effects of on-farm management 
alternatives on surface water resources. 

The evaluation of the biological resource considers the effects of 
on-farm management alternatives on the fauna and flora of the study 
area. The degree of change in quality and habitat type or composition 
that may result from a particular management practice provides the 
criteria for evaluation of the biological resource. 

The agricultural lands resource may show the most obvious effects 
resulting from the implementation of certain on-farm management 
alternatives. Changes in cropping patterns/ additions of sprinkler 



7- 4 



irrigation systems/ drainage of lands/ and removal of some lands from 
production may affect this resource. Criteria for evaluating this 
resource consider the anticipated effects of each on-farm management 
pract ice . 

7.1.4 Legal/Institutional Feasibility 

Legal/institutional feasibility refers to rules and regulations 
that may affect the implementation of management decisions. Rules 
and regulations generally fall into rour categories: 1) water 
quality criteria for drainage discharges; 2) flexibility of water 
deli veries 'to the grower; 3) water marketing and pricing policies; 
and 4) legal design criteria for establishing storage ponds for toxic 
wastes. Water quality criteria are established by state and federal 
regulations and apply to the overall management objectives of this 
study. The flexibility of water deliveries impacts a grower's 
decision on the selection of management practices that can be 
implemented. For example/ good irrigation scheduling requires a 
very flexible water delivery system. Regulations on water 
marketing and pricing affect economic decisions. For example/ if 
water saved can be sold outside the grower's water district/ then an 
incentive for improving irrigation efficiency can be established. 
Design criteria for storage/evaporation ponds are established by the 
State Water Quality Control Board according to legal requirements. 
The cost of implementing design criteria affects the size of the 
ponds and is balanced against the cost of implementing other 
management practices to reduce deep percolation. Various 
management practices are therefore judged with respect to the 
overall effect that legal/institutional considerations have on 
their implementation. 

7.1.5 Social 

The social ramifications of implementing various on-farm management 
alternatives are potentially far reaching. Social criteria that 
should be considered for evaluation are the human resources and 
social services in the area. 

The human resource of the area encompasses the local labor pool 
including farm workers. On-farm management practices that change 
current agricultural production could therefore affect changes in 
this resource. For example/ the implementation of automated 
irrigation systems could ultimately reduce the number of jobs in the 
area while use of more intensive surface irrigation systems could 
increase employment- 

The indirect effects of changes in the agricultural economy are 
ultimately expressed through their effects on population, business 
and social services in the affected area. These factors may be 
either positively or negatively impacted. Therefore, on-farm 
management alternatives that are being considered are evaluated 
regarding their overall effect on the social services of the area. 



7- 5 



7.2 EVALUATION APPROACH 

On-Farm management alternatives were evaluated with respect to their 
feasibility under each of the criteria listed under technical/ 
economic/ legal/institutional/ environmental/ and social con- 
straints. The overall feasibility of each management alternative 
was also determined addressing factors likely to limit the 
implementation of a particular management practice. 

Evaluations are given as subjective rankings and should not be 
construed as definitive criteria for implementation of management 
alternatives. Rankings may be subject to change as new information 
becomes available. Also/ the feasibility of implementing 
management alternatives may vary depending on soil/ climate/ 
topography/ cropping practices/ the type of irrigation water 
delivery system/ and overall farming practices. The implementation 
of these practices on an individual farm will require a systems 
approach analysis to address these variable resource and management 
conditions . 

7.2.1 Detailed Evaluation 

In order to evaluate the relative feasibility of implementing the 
various on-farm management alternatives with respect to technical/ 
economic/ legal/institutional/ environmental/ and social con- 
straints/ a method of comparing alternatives was required. Since 
the evaluation criteria are primarily subjective in nature/ 
qualitative rankings were given for each management alternative and 
evaluation criteria. For each evaluation criteria/ a ranking of 1/ 
2/ or 3 was given where 1 is the lowest and 3 the highest feasibility. 
A weighting factor was then applied to each ranking with the 
summation used to provide a total relative evaluation of each 
management alternative. Weighting factors applied are based on the 
expected significance of the evaluation criteria relative to the 
feasibility of implementing particular management practices. 

7.2.2 Feasibility Rankings 

Using the above rationale and approach for an initial evaluation 
provides the basic information to aid in making qualitative rankings 
of the overall feasibility of an on-farm management alternative. 
The following discussion provides definitions of the overall 
feasibility rankings. 

On-farm management alternatives that have been discussed and/or 
reviewed in the context of this study have been effectively used in 
either actual on-farm situations or research trials. The major 
difference among the alternatives that prGvide a technical solution 
to the problem is the level of knowledge needed to effectively apply 
the practice. This level of knowledge equates to ease of 
implementation and use of technology by the grower. 



7- 6 



When reviewing the technical 
must be made regarding its 
western San Joaquin Valley 
determination incorporates 
identified in Section 7.1 



ranking . 
follows : 



aspects of an alternative, a decision 
technical feasibility for a typical 
farming operation. This feasibility 
the technical evaluation criteria 
and assigns a relative feasibility 



The degrees of technical feasibility are defined as 



3 (High): This level of technical feasibility equates to the 
most feasible regarding implementation from a technical 

this category all the technical criteria are 
the technical solution available, the 
alternative being easy to use, implement, and maintain from a 
technical standpoint, and the time frame to implement the 

a major interference with on-farm operations. 



standpoint 
easily met 



In 
with 



alternative not 



o 2 (Medium): This category of feasibility equates to a mid-range 
level of feasibility from a technical standpoint. In this 
category some of the evaluation criteria can only be met with 
some degree of difficulty. The technical solution and 
availability of the technology must be easily met. However, 
constraints with implementation and use and/or maintenance are 
sufficient to reduce an alternative to a medium degree of 
technical feasibility. Additionally, significant time con- 
straints imposed on other on-farm operations resulting from 
implementation of an alternative are reason for medium 
feasibility. 

o 1 (Low): A low technical feasibility results from the fact that 
using or implementing an alternative can only be achieved with a 
high degree of difficulty. Unproven technologies, major 
implementation inputs, and specialized knowledge needed for use 
and maintenance are criteria that significantly affect the 
technical feasibility of an alternative resulting in a low 
rating . 

The economic feasibility of specific on-farm alternatives is 
difficult to quantify because of the differences in production 
techniques, perception of market behavior, and financial conditions 
of growers throughout the westside of the San Joaquin Valley. A 
complete economic feasibility study requires estimating all costs 
and returns expected from a given development or implemented 
management alternative and can usually be accomplished on an 
individual farm basis. Aggregate information can often be useful 
for planning and evaluation purposes. Therefore, the economic- 
feasibility evaluation conducted for the purpose of this study will 
only look at relative cost, benefits, life expectancy, and possible 
economic incentives that may be associated with a given practice or 
set of practices. 

For purposes of discussion, the economic feasibility of an on-farm 



7- 7 



management alternative has been reduced to a relative ranking index 
that is defined as follows: 

o 3 (High): A high level of economic feasibility exists for 
implementing an alternative if all costs are relatively low and 
significant management and/or labor inputs are not required. 
Reductions in crop yields or increased production costs are 
negligible. Additional farm machinery is not required to 
implement and/or maintain an alternative. 

o 2 (Moderate): This category of economic feasibility defines a 
midpoint for economic costs and benefits associated with the 
implementation of an on-farm practice. Costs associated with 
these practices can be viewed in two ways. First/ fixed and 
variable costs are in a range that might have an effect on the net 
return under the current cropping pattern. Secondly/ losses in 
revenues or net return which are attributable to reduced yields 
or changes in cropping patterns may begin to affect the 
profitability of an operation. Additional farm equipment may 
be needed to implement some of the alternatives in the moderate 
category. 

o 1 (Low): This category of economic feasibility includes those 
management alternatives that may not be feasible because costs 
exceed benefits. This would include alternatives that require 
significant management and labor for implementing or would 
require major capital investments. In addition/ practices or 
alternatives which cause changes in cropping that would 
adversely affect net returns are included in this category along 
with short-lived/ high cost alternatives. 

Feasible economic alternatives identified by this approach are 
considered approximations. Detailed farm-specific economic anal- 
ysis is the only reliable method on which these items can be 
specifically evaluated. In addition, significant gaps exist in the 
literature and research of economic impacts and/or costs associated 
with many of the on-farm management alternatives. 

Many on-farm management alternatives have the potential for 
impacting the local environment both from a positive and negative 
standpoint. Irrigation water conservation practices may positively 
affect one resource while negatively impacting another. For 
example/ reducing deep percolation losses through increased 
irrigation efficiency may reduce subsurface drainage flows of poor 
quality water/ a positive effect/ while at the same time negatively 
impacting the soil resource through increased salinization of the 
soil profile. In order to deal with this type of situation when 
determining the environmental impacts of an on-farm management 
alternative/ consideration must be given to those resources that 
will be impacted the greatest and that are the most difficult to 
ameliorate once they have been degraded. Therefore/ because the 
primary emphasis of this study is to reduce subsurface drainage flow 



7- 8 



and increase quality of the drainwater, priority is given to those 
alternatives that do not impact the surface water and groundwater 
resources. These resources indirectly affect the other resources, 
given the present land use. 

Categories that have been developed for evaluating the environmental 
impact of implementing a practice are defined as follows: 

o 3 (Positive): This category of environmental impact identifies 
those management alternatives that, through implementation, 
will show or cause a positive impact on one or more of the 
resources summarized in Section 7.1.3 of this report. 

o 2 (None): This category identifies those management 
alternatives that will have very little to no effect on the 
resources of the local environment. Short- and long-term 
effects are considered when placing an on-farm management 
alternative into this category. 

o 1 (Negative): The negative environmental impact category pro- 
vides a mechanism for flagging or identifying those on-farm 
management alternatives that have the potential to negatively 
impact the resources of the area. 

This approach to evaluating the impacts of on-farm management 
alternatives on the soil, hydrologic, biological, and agricultural 
resources of the area is not without fault. The degree and intensity 
of a given impact is not considered or was the effect caused by 
interaction of alternatives on the above resources. A multi- 
resource impact caused by implementation of an on-farm alternative 
is of considerable importance; however, there is little research 
that considers these effects. 

Legal and/or institutional aspects of implementing on-farm 
alternatives play a major role in whether or not a particular 
alternative can be implemented. The procedures for evaluating the 
legal aspects are rather straight forward. However, institutional 
aspects must not only conform to legal issues, but also consider 
regulations that may be imposed by water districts, drainage 
districts, and federal and state governing boards. The criteria for 
evaluating legal/institutional constraints are summarized as 
follows : 



o 3 (None): Legal/institutional constraints 
management alternatives do not exist. 



to implementing 



o 2 (Moderate): Legal/institutional constraints to implementing 
management alternatives exist but they can be easily resolved. 

o 1 (Severe): Legal/institutional constraints to implementing 
management alternatives exist which can not be easily resolved. 



7- 9 



The implementation of various on-farm management practices may have 
an impact on the social environment of the study area. When 
evaluating the social implications resulting from implementation of 
on-farm management practices/ the effect on the human resource is of 
primary concern. The relative categories on which to evaluate 
social effects consist of positive impacts, no impacts, and negative 
impacts. They are defined as follows: 

o 3 (Positive): This category of social impact basically 
addresses the human resource in that the potential labor pool is 
positively impacted through the implementation of the subject 
on-farm management alternative. In this category, additional 
labor may be needed which could result in new jobs and increased 
tax base for the area. 

o 2 (None): This category relates to those practices or 
alternatives that have no effect on the current social 
environment of the community. 

o 1 (Negative): The negative category comprises those on-farm 
management practices that detract from the social environment. 
Practices that would result in a reduced labor requirement or 
lower tax base would be considered to have a negative impact. 

The preceding discussion has identified the methodology that was 
used to evaluate the on-farm management alternatives presented in 
this report. A simple evaluation procedure for each alternative, 
using the criteria presented in Section 7.1, provides insight into 
the overall feasibility of an on-farm management alternative. 
However, it is important when evaluating an on-farm management 
alternative to consider the total integrative effect of an 
alternative on the technical, economic, environmental, legal/insti- 
tutional and social aspects of the area. 

7.2.3 Matrix Evaluation Method 

In order to effectively evaluate an on-farm management alternative 
using the methodology described in Section 7.2.1, a logical method of 
presentation is needed. In addition, this method of presentation 
should provide a mechanism to compare the feasibility and/or impact 
of an alternative. The approach selected uses a matrix format for 
presentation of the evaluation results. 

7.2.4 Overall Feasibility Determinations 

Overall feasibility rankings were determined from a compilation of 
individual technical, economic, environmental, legal/institu- 
tional, and social constraints. Rankings were given as high, 
medium, and low with respect to each alternative's feasibility for 
implementation as a management practice on the westside of the San 
Joaquin Valley. These rankings were applied based on information 
from the literature review, grower interviews, discussions with 



7- 10 



individuals from public agencies, and the experience and judgement 
of the Boyle project team. Potential limitations to implementing 
management practices were also noted. The feasibility ranking 
indicated may not accurately represent conditions on all farms in the 
project area because of variable natural resource, financial, and 
management factors which occur. This necessitates the application 
of a systems approach which can be initially guided by the management 
alternative feasibility evaluation. A systems approach is defined 
as the consideration of combinations of alternative practices that 
must be evaluated by the individual farming unit. 

7.3 EVALUATION RESULTS 

7.3.1 Technical Evaluation 

Rankings of technical evaluation criteria are given in Table 7.2. 
Weighting factors are applied to determine the overall feasibility 
ranking for each alternative. Weighting factors are determined 
based on the expected relative importance of each evaluation 
criterion. The effectiveness of irrigation management practices to 
reduce deep percolation is generally high. Some practices are not 
ranked highly because their effectiveness has yet to be demonstrated 
or their overall effect is negligible. Measures to reuse water are 
highly effective since they reduce the amount of drainage flow that 
needs to be stored and treated. Crop management practices are low to 
moderately effective since these practices will have little effect 
on reducing deep percolation losses. The use of salt/boron tolerant 
crops for drainage water reuse without dilution would be a highly 
effective alternative management practice. The most highly 
effective crop management practice is fallowing since there would be 
no irrigation requirement and thus no deep percolation due to 
irrigation. However, drainage problems could continue because of 
inefficient upslope irrigation. The most effective technical 
solution under soil management would be leveling and grading of the 
land surface. This practice will allow better water distribution 
for surface irrigation systems. Management of irrigation flows 
with gates or similar devices will directly reduce drainage flows. 
Storage/evaporation ponds may be needed as an element of the farm 
drainage water management plan to effectively prevent off-farm 
drainage flows. Reduction and precipitation of selenium in the soil 
or in tile drains and bioaccumulation of selenium by plants have as 
yet not been shown to be effective in reducing subsurface drainage 
flows or improving subsurface drainage water quality. 

The availability of various management practices is highly variable. 
Most products or management techniques are currently available and 
are being used commercially. Several relatively new technologies 
that are only beginning to be introduced in California include 
cablegation, volumetric water application for furrow and basin- 
check irrigation systems, time-domain ref lectometry for irrigation 
scheduling, surge irrigation, and surface-drained level basins. 
The technology for reusing subsurface drainage waters is available 

7- 11 



2 3 3 2 

3 3 2 2 

2 12 2 

3 3 2 2 
3 3 2 3 
3 3 2 3 

3 3 12 

3 3 2 2 

3 2 2 2 

3 3 13 

3 3 3 3 

2 3 2 2 



2 3 3 3 

2 3 2 1 

2 3 2 1 

3 3 2 2 

2 12 2 

3 3 2 2 
3 3 2 3 

3 3 3 3 

3 3 2 2 



3 3 13 

3 3 13 

2 3 2 2 

2 3 2 3 

2 3 12 

3 3 12 
3 3 12 

3 3 12 

3 3 12 



3 


25 


3 


22 


2 


24 


2 


36 


3 


41 


3 


41 



TABLE 7.2 
TECHNICAL FEASIBILITY RANKINGS FOR ON-FARM MANAGEMENT ALTERNATIVES 



Ease of Ease of 
Etfec- Avail- Implemen- Operation & Time to Total 

Alternative tiveness ability tation Maintenance Implement Ranking 2 / 

(5) y VWy TTTTT (TTTT (lU/ 

IRRIGATION HATER CONSERVATION 

On-Farro Conveyance System 

Ditch S Canal Linings 

o Bentonite 2 2 2 1 

o Chemical Sealants 2 12 1 

o Membrane Linings 2 2 2 1 

o Concrete 3 3 2 2 
Pi pe 1 ines 

o Concrete 3 3 2 3 

o Metal 3 3 2 3 

Irrigation Management 

Water Control 

o Siphons and Tubes 
o Surge-Flow 
o Cablegation 
Water Measurement 
o Weirs/Flumes 
o Propeller-type 
o Pitot Tube 
Water Application 
Surface Systems 

o Shortening Run Lengths 

o Return Flow Systems 

o Volumetric Water Application 
Sprinkler Systems 

o Increase Overlap 

o Alternate Sets 

o Avoid Windy Periods 

Irrigation Scheduling 

Soil Moisture Deficit 

o Feel Method 

o Tensiometer 

o Gypsum Bock 

o Neutron Probe 

o Time Domain Ref lectometry 

o Leaf Water Potential 

o Canopy Temperature 
Water Budget 

o Reducing Pre-irr igat ion 

o Irrigation Management 
Programs 

Irrigation Methods 

Surface Systems 

o Level Basin 

o Surface-drained Level Basin 
Sprinkler Systems 

o Hand Move 

o Solid Set 

o Center Pivot 

o Linear Move 

o Travel Trickle 
Trickle/Drip Systems 

o Surface Trickle 

o Subsurface Trickle 



3 


33 


3 


37 


3 


26 


3 


37 


3 


41 


3 


41 


2 


35 


2 


36 


2 


33 


2 


38 


3 


42 


3 


32 



3 


37 


2 


27 


2 


27 


2 


36 


2 


25 


3 


37 


3 


41 


3 


42 


3 


37 



2 


39 


1 


38 


2 


31 


2 


35 


2 


30 


2 


35 


2 


35 


2 


35 


2 


35 



7-12 



Table 7.2, Continued 



Alternative 



DRAINAGE WATER REUSE 



Ease of Ease of 2/ 

Effec- Avail- Implemen- Operation & Time to Total" 
tiveness ability tation Maintenance Implement Ranking 



(5) 1/ nuT 



(1)1/ 



(4)1/ 



[1)1/ 



Reuse with Blending 
Reuse without Blending 
Growth Stage Application 
Subsurface Irrigation 



28 
28 
20 
20 



CROP MANAGEMENT 



o Increased Plant Density 

o Variable Spacing 

o Transplanting 

o Early Plant Date 

o Water Efficient Crops 

o Salt/Boron Tolerant Crops 

o Agroforestry 

o Fallowing 



23 
23 
19 
32 
35 
30 
32 
42 



SOIL AND SUBSURFACE DRAINAGE 
MANAGEMENT 



Land Leveling and Grading 
Deep Tillage 
Organic Matter Incorp. 
Drainage System Control 



36 

27 
25 
20 



ON-FARM STORAGE/TREATMENT/DISPOSAL OF 
DRAINAGE WATER 



Storage/Evaporation Ponds 
Immobilization of Se 
Bio-Accumulation of Se 



36 
14 
14 



1^/ Weighting factor 

2/ Summation of individual criteria ranking x weighting factor: High 2.^^' 
Medium 27-34: and Low < 27 



7-13 



but not yet extensively used. The technology for variable spacing 
of cotton has been developed in west Texas* but this practice has not 
been used in California. The use of transplants and agroforestry 
practices is available but they are being used very little because of 
economic and market considerations. Techniques for fixing selenium 
in the soil or bioaccumulat ion are not yet available. 

The ease with which various management practices can be implemented 
is highly variable. In many cases a highly technical implementation 
procedure such as laser leveling or installation of a linear move 
irrigation system will be performed by an outside firm rather than 
the farmer. As may be expected/ the more highly technical the 
alternative, the more difficult it will be to implement. This 
difficulty will be reflected primarily in the cost of installation. 
Those irrigation water management practices that may be difficult to 
implement because of costs are shortening furrow run lengths and 
installing a return flow system. Irrigation systems that may be 
expensive to implement may include level basin systems, linear move 
and center-pivot systems, and subsurface trickle systems. Water 
reuse systems will be relatively expensive to install. In general, 
crop and soil management practices will be easier to implement if the 
proper farm equipment is available. Treatment technologies will be 
relatively difficult to implement. 

Ease of operation and maintenance is a technical factor that will be 
very important to the grower. Concrete-lined ditches and pipelines 
require little maintenance and are therefore ranked high. 
Temporary ditch and canal linings require more maintenance and are 
therefore not ranked as high. Water control and measuring devices 
can be relatively easy to use with those requiring very little 
technical expertise ranking the highest. Examples of these are 
propeller-type and pitot tube in-line meters. Of the irrigation 
scheduling techniques, tensiometers and gypsum blocks are probably 
the most difficult to maintain, especially where row crops are grown. 
The easiest to use is probably the infrared gun for detecting changes 
in plant temperatures. Of the surface irrigation systems, the level 
basin systems are much easier to manage than traditional surface 
irrigation methods. Of the sprinkler systems, the solid set system 
is easiest to manage but is generally restricted to permanent crops. 
Sprinkler systems in general, however, require careful maintenance 
for optimum irrigation application efficiency. The water reuse 
techniques are difficult to manage except for direct tailwater or 
drainage water recovery systems. In general, subsurface irrigation 
is not by design, although technical expertise is required to fully 
utilize this water supply for crop growth. Crop management 
practices that do not require changes in field operations and 
harvesting practices are generally considered easy to implement. 
These practices include changing to an earlier planting date or to a 
different crop variety. In contrast, changing plant spacing or 
changing to a different crop may require different field operation 
and harvesting practices. At this time, there is no mechanical 
means to transplant row crop seedlings in the field. Soil 



7- 14 



management practices are only moderately easy to use since they 
require special equipment with more extensive operation and 
maintenance requirements. Of the on-farm disposal practices/ 
storage and evaporation ponds are relatively easy to maintain and 
operate once they have been installed. However, hazing and leachate 
collection systems in Class I ponds, if required, could be difficult 
to operate and maintain. The ease with which selenium can be 
immobilized in soils or accumulated in plant tissues in ponds or 
farmlands is not well known at this time. Further, considerable 
effort may be required to protect wildlife from entering storage and 
evaporation ponds, especially those contaminated with selenium. 

Most alternative management technologies can be implemented without 
disrupting the cropping cycle and thus are not a time constraint. 
Those practices that may take longer than a year to implement are 
agrof orestry , selenium immobilization, and bioaccumulation prac- 
tices. 

7.3.2 Economic Evaluation 

Rankings of economic evaluation criteria are given in Table 7.3. 
The economic comparison considers life expectancy and annual fixed 
and variable costs. The highest numerical ranking has the lowest 
cost . 

For conveyance structures, membrane liners have lower life 
expectancy compared to concrete-lined ditches and pipes. Water 
control and measurement devices and water application improvement 
technologies are generally long-lived. Trickle irrigation systems 
for row crops might have a life expectancy of as little as one year 
although longer durations, especially for subsurface trickle 
systems, are becoming more commonplace with advances in drip tube 
manufacturing and farming technology. Life expectancy is 
indeterminant with respect to crop and soil management practices. 

Fixed costs are those associated with the purchase and installation 
of a management alternative. Because of the limited available data, 
numerical rankings may not accurately identify the relationships 
between the different alternatives. Some of the more costly 
alternatives include concrete-lined ditches and pipelines, return 
flow systems, level basin systems, sprinkler systems, drip/trickle 
systems, transplanting operations, laser leveling, and evaporation 
ponds . 

Variable costs are those associated with the operation and 
maintenance of a management alternative. Included are costs of 
repair, fuel and electricity, and labor. Once installed, pipelines 
should require little additional expense for operation and 
maintenance compared to less permanent lining materials. Water 
control and measurement systems generally require small additional 
annual expense after installation with the exception of siphons and 
tubes which have a high annual labor requirement. Automated 

7- 15 



TABLE 7.3 

ECONOMIC FEASIBILITY RANKINGS FOR 

ON-FARM MANAGEMENT ALTERNATIVES 





Life 




Vari- 


t 




Expect- 


Fixed 


iable 


Total" 


Alternative 


ancy 


Costs 


Costs 


Rankinc 




(2) 1/ 


(5)1/ 


(4)1/ 




IRRIGATION WATBl CXJNSERVATION 










On-Farm Conveyance System 










Ditch & Canal Linings 










o Bentonite 


2 


2 


2 


22 


o Chemical Sealants 


1 


2 


1 


16 


o Membrane Linings 


2 


1 


2 


17 


o Concrete 


3 


1 


2 


19 


Pipelines 










o Concrete 


3 


2 


3 


28 


o Metal 


3 


2 


3 


28 


Irrigation Management 










Water Control 










o Siphons and Tubes 


3 


3 


1 


25 


o Surge-Flow 


3 


3 


3 


33 


o Cablegation 


2 


2 


2 


22 


Water Measurement 










o Weirs/Flumes 


3 


2 


2 


24 


o Propeller-type 


3 


3 


3 


33 


o Pi tot Tube 


2 


3 


3 


31 


Water Application 










Surface Systems 










o Shortening Run Lengths 


3 


1 


3 


23 


o Return Flow Systems 


3 


2 


2 


24 


o Volumetric Water Application 3 


2 


3 


28 


Sprinkler Systems 










o Increase Overlap 


3 


2 


2 


24 


o Alternate Sets 


3 


2 


2 


24 


o Avoid Windy Periods 


3 


3 


3 


33 


Irrigation Scheduling 










Soil Moisture Deficit 










o Feel Method 


3 


3 


3 


33 


o Tensiometer 


2 


2 


2 


22 


o Gypsum Bock 


2 


2 


2 


22 


o Neutron Probe 


3 


2 


2 


24 


o Time Domain Reflectometry 


3 


2 


2 


24 


o Leaf Water Potential 


3 


3 


2 


29 


o Canopy Temperature 


3 


3 


2 


29 


Water Budget 










o Reducing Pre-irrigation 


3 


3 


2 


29 


o Irrigation Management 










Programs 


3 


2 


2 


24 



2/ 



7-16 



Table 7.3/ continued 





Life 




Vari- 


2/ 




Expect- 


Fixed 


iable 


Total 


Alternative 


ancy 


Costs 


Costs 


Ranking 




(2) 1/ 


(5)1/ 


(4)1/ 




Irrigation Methods 










Surface Systems 










o Level Basin 


3 


1 


2 


19 


o Surface-drained Level Basin 


3 


1 


2 


19 


Sprinklec Systems 










o Hand Move 


3 


1 


1 


15 


o Solid Set 


3 


1 


2 


19 


o Center Pivot 


3 


1 


2 


19 


o Linear Move 


3 


1 


2 


19 


o Travel Trickle 


3 


1 


2 


19 


Trickle/Drip Systems 










o Surface Trickle 


2 


1 


3 


21 


o Subsurface Trickle 


2 


1 


3 


21 


DRAINAGE WATER RFIISE 










o Reuse with Blending 


3 


2 


2 


24 


o Reuse without Blending 


2 


2 


3 


26 


o Growth Stage Application 


3 


2 


2 


24 


o Subsurface Irrigation 


3 


3 


3 


33 


CROP MANAGEMENT 










o Increased Plant Density 


3 


3 


2 


29 


o Variable Spacing 


3 


3 


2 


29 


o Transplanting 


3 


1 


1 


15 


o Early Plant Date 


3 


3 


3 


33 


o Water Efficient Crops 


3 


3 


3 


33 


o Salt/Boron Tolerant Crops 


3 


3 


3 


33 


o Agroforestry 


3 


2 


2 


24 


o Fallowing 


3 


3 


1 


25 


SOIL AND SUBSURFACE DRAINAGE 










MAN^EM£NT 










o Land Leveling and Grading 


3 


1 


2 


19 


o Deep Tillage 


2 


1 


3 


21 


o Organic Matter Incorp. 


1 


3 


2 


25 


o Drainaae Svstem Control 


2 


2 


2 


22 



ON-FABM STORAGE/TREATMENT/DISPOSAL OF 
DRAINAGE WATER 

o Storage/Evaporation Ponds 
o Immobilization of Se 
o Bio-Accumulation of Se 



2 


2 


2 


22 


1 


2 


2 


20 


1 


2 


2 


20 



1/ Weighting factor 

2/ Summation of individual criteria ranking x weighting factor; 
Low Cost >25; Medium Cost 18-24; and High Cost <18. 



7-17 



sprinkler irrigation systems (center-pivot, linear move/ travel 
trickle/ etc.) have high fixed costs but variable costs are often 
lower because of reduced labor requirements. However, savings in 
labor costs may be somewhat offset by higher energy costs. Further, 
maintenance requirements may be appreciable for these systems. The 
most costly irrigation systems to operate are hand-move sprinklers 
and traditional furrow irrigation systems because of extensive labor 
requirements. Variable costs for irrigation scheduling will 
primarily result from the labor requirements necessary for 
monitoring soil moisture. Once installed, return flow systems will 
have moderate maintenance costs. 

7.3.3 Environmental Evaluation 

Environmental criteria were evaluated as summarized in Table 7.4 
with respect to the soil, groundwater/ biological, and agricultural 
land resources. Since these criteria largely relate to the overall 
objective to reduce drainage flows and improve drainage water 
quality, evaluations are general in nature. 

The soil resource will be adversely affected by those practices that 
increase soil salinity, reduce soil infiltration rates, increase 
toxic elements, or reduce overall fertility. In general, 
irrigation water conservation practices increase the salinity of the 
soil profile. Recycling subsurface drainage water may have an 
adverse impact if high salt and boron loads are added to the soil. 
Leveling practices result in cut and fill operations which remove 
better quality top soil from cuts and potentially reduce soil 
fertility and tilth in cut areas. Other alternative management 
practices should have little effect on the soil resource other than 
that expected from normal field operations. 

The groundwater resource should be favorably impacted since 
management practices reduce deep percolation to the shallow 
groundwater table. The degree of favorable impact should correlate 
with the effectiveness of the technical solution. An adverse impact 
may result from seepages occurring beneath unlined evaporation 
ponds. The surface water resource should also be enhanced as a 
result of the management alternatives since subsurface drainage 
flows released to surface water supplies will be reduced. 

Little on-farm biological impact would be expected from most 
alternative management practices. However, certain practices such 
as agroforestry may enhance the population of native flora and fauna 
while fallowing would have the opposite effect. Certain practices 
may also be detrimental if they introduce toxic constituents into the 
food chain. Examples are constructing evaporation ponds and 
planting selenium accumulator vegetation. The off-farm disposal of 
waste from evaporation ponds or selenium treatment methods may also 
have a negative environmental impact. 



7- 18 



TABLE 7.4 

ENVIRONMENTAL IMPACT RANKINGS FOR 

ON-FARM MANAGEMENT ALTERNATIVES 



Environmental Total 

Alternative ^ Impact Ranking 2/ 

_ ^—^ 

IRRIGATION WATER CONSERVATION 

On-Farm Conveyance System 
Ditch & Canal Linings 

o Bentonite 2 8 

o Chemical Sealants 1 4 

o Membrane Linings 2 8 

o Concrete 2 8 
Pipelines 

o Concrete 2 8 

o Metal 2 8 
Irrigation Management 
Water Control 

o Siphons and Tubes 2 8 

o Surge-Flow 2 8 

o Cablegation 2 8 
Water Measurement 

o Weirs/Flumes 2 8 

o Propeller-type 2 8 

o Pitot Tube 2 8 
Water Application 
Surface Systems 

o Shortening Run Lengths 2 8 

o Return Flow Systems 2 8 

o Volumetric Water Application 2 8 
Sprinkler Systems 

o Increase Overlap 2 8 

o Alternate Sets 2 8 

o Avoid Windy Periods 2 8 
Irrigation Scheduling 
Soil Moisture Deficit 

o Feel Method 2 8 

o Tensiometer 2 8 

o Gypsum Bock 2 8 

o Neutron Probe 2 8 

o Time Domain Ref lectometry 2 8 

o Leaf Water Potential 2 8 

o Canopy Temperature 2 8 
Water Budget 

o Reducing Pre-irr igat ion 2 8 

o Irrigation Management 2 8 
Programs 



7- 19 



Table 7.4, continued 



Environmental Total 

Alternative Impact Ranking 2 / 

(4) 1/ 
Irrigation Methods 
Surface Systems 

o Level Basin 2 8 

o Surface-drained Level Basin 2 8 
Sprinkler Systems 

o Hand Move 2 8 

o Solid Set 2 8 

o Center Pivot 2 8 

o Linear Move 2 8 

o Travel Trickle 2 8 
Trickle/Drip Systems 

o Surface Trickle 2 8 

o Subsurface Trickle 2 8 

DRAINAGE WATER REUSE 

o Reuse with Blending 1 4 

o Reuse without Blending 1 4 

o Growth Stage Application 1 4 

o Subsurface Irrigation 2 8 

CROP MANAGEMENT 

o Increased Plant Density 2 8 

o Variable Spacing 2 8 

o Transplanting 2 8 

o Early Plant Date 2 8 

o Water Efficient Crops 2 8 

o Salt/Boron Tolerant Crops 2 8 

o Agroforestry 2 8 

o Fallowing 2 8 

SOIL AND SUBSURFACE DRAINAGE 
MANAGEMENT 

o Land Leveling and Grading 2 8 

o Deep Tillage 2 8 

o Organic Matter Incorp. 2 8 

o Drainage System Control 3 12 

ON-FARM STORAGE/TREATMENT/DISPOSAL OF 
DRAINAGE WATER 

o Storage/Evaporation Ponds 2 8 

o Immobilization of Se 1 4 

o Bio-Accumulation of Se 1 4 



\_/ Weighting factor. 

2_/ Individual criteria ranking x weighting factor. Highest rank 
represents the most favorable environmental impact. 

7- 20 



7.3.4 Legal/Institutional Evaluation 

Legal and institutional constraints may markedly affect farm 
management decisions. The evaluation of legal and institutional 
constraints as related to the management alternatives is summarized 
on Table 7.5. 

Water quality criteria are directly reflected in drainage discharge 
requirements for subsurface drainage water- Where off-farm 
drainage is not allowed, management operations will be affected in 
areas with an immediate drainage problem. In areas without an 
existing need for subsurface drainage systems, management 
operations are not presently affected, although these areas may 
contribute to the drainage problem. Water quality standards 
presently address point source discharges into surface and 
groundwaters. Subsurface drainage flows from individual fields or 
farms are not presently considered point source discharges. Future 
regulatory decisions could necessitate improving on-farm manage- 
ment practices to reduce subsurface drainage flows and recycle or 
store collected subsurface drainage waters. 

The flexibility of the water delivery system to the farm directly 
affects the implementation of good irrigation scheduling practices. 
In general, the older, open conveyance systems are the least 
efficient in providing water on demand, requiring a long advance 
notice before irrigating and not providing the exact quantity needed 
at the correct flow rate. 

The cost of irrigation water directly affects decisions to improve 
irrigation efficiency. Higher irrigation efficiency is evident in 
State Water Project service areas in the southern San Joaquin Valley 
where water prices are relatively high compared to federal service 
areas. The ability of individual growers or water agencies to sell 
water outside the water district is restricted by federal and state 
regulations and policies and therefore, an incentive to improve 
irrigation efficiencies seem to be foregone. Even if water sales 
outside the district are allowed, the annual water allotment may be 
subject to reduction if it can be demonstrated that less water is 
required for existing agricultural practices. The threat of this 
occurrence may therefore inhibit water sales or transfers out of a 
water district. 




7.3.5 Social Evaluation 

The evaluation of the impact of management alternatives on social 
conditions in the project area is summarized on Table 7.6. The 
effect of various management practices on labor requirements will 

7- 21 



TABLE 7.5 

LEGAL/INSTITUTIONAL FEASIBILITY RANKINGS 

FOR ON-FARM MANAGEMENT ALTERNATIVES 



Legal/ Total 

Alternative Institutional Ranking 2 / 

(4) 1/ 
IRRIGATION WATER CONSERVATION 

On-Farm Conveyance System 
Ditch & Canal Linings 

o Bentonite 3 12 

o Chemical Sealants 2 8 

o Membrane Linings 3 12 

o Concrete 3 12 

Pipelines 

o Concrete 3 12 

o Metal 3 12 

Irrigation Management 
Water Control 

o Siphons and Tubes 3 12 

o Surge-Flow 3 12 

o Cablegation 3 12 

Water Measurement 

o Weirs/Flumes 3 12 

o Propeller-type 3 12 

o Pitot Tube 3 12 

Water Application 
Surface Systems 

o Shortening Run Lengths 3 12 

o Return Flow Systems 3 12 

o Volumetric Water Application 3 12 

Sprinkler Systems 

o Increase Overlap 3 12 

o Alternate Sets 3 12 

o Avoid Windy Periods 3 12 

Irrigation Scheduling 
Soil Moisture Deficit 

o Feel Method 3 12 

o Tensiometer 3 12 

o Gypsum Bock 3 12 

o Neutron Probe 3 12 

o Time Domain Ref lectometry 3 12 

o Leaf Water Potential 3 12 

o Canopy Temperature 3 12 

Water Budget 

o Reducing Pre-irr igat ion 2 8 

o Irrigation Management 3 12 

Programs 



7- 22 



Table 7.5, continued 



Legal/ Total 

Alternative Institutional Ranking 2 / 

(4) 1/ 
Irrigation Methods ~ 

Surface Systems 

o Level Basin 3 3^2 

o Surface-drained Level Basin 3 12 

Sprinkler Systems 

o Hand Move 3 12 

o Solid Set 3 12 

o Center Pivot 3 12 

o Linear Move 3 12 

o Travel Trickle 3 12 

Trickle/Drip Systems 

o Surface Trickle 3 12 

o Subsurface Trickle 3 12 

DRAINAGE WATER REUSE 

o Reuse with Blending 3 12 

o Reuse without Blending 3 12 

o Growth Stage Application 3 12 

o Subsurface Irrigation 3 12 

CROP MANAGEMENT 

o Increased Plant Density 3 12 

o Variable Spacing 3 12 

o Transplanting 3 12 

o Early Plant Date 2 8 

o Water Efficient Crops 3 12 

o Salt/Boron Tolerant Crops 3 12 

o Agroforestry 3 12 

o Fallowing 3 12 

SOIL AND SUBSURFACE DRAINAGE 
MANAGEMENT 

o Land Leveling and Grading 3 12 

o Deep Tillage 3 12 

o Organic Matter Incorp. 3 12 

o Drainage System Control 3 12 

ON-FARM STORAGE/TREATMENT/DISPOSAL OF 
DRAINAGE WATER 

o Storage/Evaporation Ponds 2 8 

o Immobilization of Se 2 8 

o Bio-Accumulation of Se 2 8 



_!/ Weighting factor 

!_/ Individual criteria ranking x weighting factor. Highest rank 
represents absence of legal/ institutional constraints. 

7- 23 



TABLE 7.6 

SOCIAL IMPACT RANKINGS FOR 

ON-FARM MANAGEMENT ALTERNATIVES 



Social Total 

Alternative Impact Rankinq 2/ 

fiy-TT 

IRRIGATION WATER CONSERVATION 

On-Farm Conveyance System 
Ditch & Canal Linings 

o Bentonite 2 4 

o Chemical Sealants 2 4 

o Membrane Linings 2 4 

o Concrete 2 4 
Pipelines 

o Concrete 2 4 

o Metal 2 4 
Irrigation Management 
Water Control 

o Siphons and Tubes 3 6 

o Surge-Flow 2 4 

o Cablegation 2 4 
Water Measurement 

o Weirs/Flumes 2 4 

o Propeller-type 2 4 

o Pitot Tube 2 4 
Water Application 
Surface Systems 

o Shortening Run Lengths 3 4 

o Return Flow Systems 3 4 

o Volumetric Water Application 3 4 
Sprinkler Systems 

o Increase Overlap 3 4 

o Alternate Sets 3 4 

o Avoid Windy Periods 3 4 
Irrigation Scheduling 
Soil Moisture Deficit 

o Feel Method 3 4 

o Tensiometer 3 4 

o Gypsum Bock 3 4 

o Neutron Probe 3 4 

o Time Domain Ref lectometry 3 4 

o Leaf Water Potential 3 4 

o Canopy Temperature 3 4 
Water Budget 

o Reducing Pre-irrigation 2 4 

o Irrigation Management 3 6 
Programs 



7-24 



Table 7.6, continued 



Social Total 

Alternative Impact Ranking 2 / 

(2) 1/ 
Irrigation Methods 
Surface Systems 

o Level Basin 1 2 

o Surface-drained Level Basin 1 2 
Sprinkler Systems 

o Hand Move 3 6 

o Solid Set 1 2 

o Center Pivot 1 2 

o Linear Move 1 2 

o Travel Trickle 1 2 
Trickle/Drip Systems 

o Surface Trickle 1 2 

o Subsurface Trickle 1 2 

DRAINAGE WATER REUSE 

o Reuse with Blending 2 4 

o Reuse without Blending 2 4 

o Growth Stage Application 2 4 

o Subsurface Irrigation 2 4 

CROP MANAGEMENT 

o Increased Plant Density 2 4 

o Variable Spacing 2 4 

o Transplanting 3 6 

o Early Plant Date 2 4 

o Water Efficient Crops 2 4 

o Salt/Boron Tolerant Crops 2 4 

o Agroforestry 2 4 

o Fallowing 1 2 

SOIL AND SUBSURFACE DRAINAGE 
MANAGEMENT 

o Land Leveling and Grading 2 4 

o Deep Tillage 2 4 

o Organic Matter Incorp. 2 4 

o Drainage System Control 2 4 

ON-FARM STORAGE/TREATMENT/DISPOSAL OF 
DRAINAGE WATER 

o Storage/Evaporation Ponds 2 4 

o Immobilization of Se 2 4 

o Bio-Accumulation of Se 2 4 



]^/ Weighting factor 

2J Individual criteria ranking x weighting factor. 

~ Highest rank represents the most positive social impact, 



7-25 



concern the farmer and community. Since it is generally believed 
that increasing labor requirements are a positive social benefit/ 
those practices with higher labor requirements are desirable from 
the community standpoint but undesirable to a farmer's economic 
condition. The largest effect on labor requirements will be related 
to the irrigation method selected. If more efficient alternative 
irrigation systems are selected/ then labor intensive irrigation 
practices (furrow and hand-move sprinkler) will be replaced by 
automated systems (surge/ linear move/ and subsurface trickle) which 
have lower labor requirements. 

7.4 EVALUATION SUMMARY 

The feasibility of each on-farm management alternative for each 
category is summarized in Table 7.7. The overall feasibility of 
each farm management alternative along with primary limitations to 
its implementation is given in Table 7.8. The results summarized in 
these tables are subject to future revision as more information 
becomes available. 

Flood/furrow irrigation is the predominant means of applying 
irrigation water in the study area. Growers have the option of 
improving existing flood/furrow systems/ applying better 
management/ and/or using other types of irrigation systems. Thus/ 
the management alternatives will either improve or modify existing 
flood/furrow irrigation systems. 

From the farmer's perspective/ economic considerations are the most 
important. Unless there is an immediate water table problem/ 
measures to reduce deep percolation and seepage losses will probably 
not be implemented unless a financial benefit can be realized. 
Those management practices most likely to be implemented are those 
with the lowest cost. Management practices that are highly feasible 
both economically and technically include most irrigation 
management practices such as water measurement and control and 
irrigation scheduling. Those management practices with the highest 
technical feasibility may also be the most costly to implement. 
Examples are installations of piped water delivery systems and new 
irrigation systems. The moderate costs of implementing drainage 
water recovery systems are compromised by the technical difficulty 
of managing the application of saline water to crops and would 
probably be used only in drainage problem areas. 

7.5 IMPLEMENTATION CONSIDERATIONS 

The implementation of management practices necessary to reduce 
subsurface drainage water volume depends on many factors as noted in 
preceding sections. The selection of the most effective management 
alternatives will depend on technical/ economic/ institutional/ 
environmental/ and social considerations. The relationship between 
these considerations is in a continuous state of flux and changes 
under different farm management operations. In almost all cases/ 



7- 26 



TABLE 7.7 
SUMMARY OF FEASIBILITY RANKINGS FOR ON-FARM MANAGEMENT ALTERNATIVES 1/ 



Technical Economic Environ- Legal/Inst i- 
f^asi- Feaai- mental tutional Social Total 
Alternative bility bility Impact Constraints Conatrainta Ranking 2 / 

IRRIGATION WATER CONSERVATION 

On-Farm Conveyance System 



Ditch & Canal Linings 
o Bentonite 

o Chemical Sealants 22 16 4 8 4 54 

o Membrane Linings 24 17 8 12 4 65 



12 4 71 

Sealants 22 16 4 

Linings 24 17 8 

o Concrete 36 19 8 12 4 79 
Pipe 1 ines 

o Concrete 41 28 8 12 4 93 

o Metal 41 28 8 12 4 93 

Irrigation Management 

Water Control 

o Siphons and Tubes 33 25 8 12 6 84 

o Surge-Flow 37 33 8 12 4 94 

o Cablegation 26 22 8 12 4 72 
Water Measurement 

o Wiers/Flumes 37 24 8 12 4 85 

o Propeller-type 41 33 8 12 4 98 

o Pitot Tube 41 31 8 12 4 96 
Water Application 
Surface Systems 

o Shortening Run Lengths 35 23 8 12 4 82 

o Return Flow Systems 36 24 8 12 4 84 

o Volumetric Water Application 33 28 8 12 4 85 
Sprinkler Systems 

o Increase Overlap 38 24 8 12 4 86 

o Alternate Sets 42 24 8 12 4 90 

o Avoid Windy Periods 32 33 8 12 4 89 

Irrigation Scheduling 

Soil Moisture Deficit 

o Feel Method 37 33 8 12 4 94 

o Tensiometer 27 22 8 12 4 73 

o Gypsum Bock 27 22 8 12 4 73 

o Neutron Probe 36 24 8 12 4 84 

o Time Domain Ref lectometry 25 24 8 12 4 73 

o Leaf Water Potential 37 29 8 12 4 90 

o Canopy Temperature 41 29 8 12 4 94 

Water Budget 

o Reducing Pre-irrigat ion 42 29 8 8 4 91 
o Irrigation Management 

Programs 37 24 8 12 6 87 

Irrigation Methods 

Surface Systems 

o Level Basin 39 19 8 12 2 80 

o Surface-drained Level Basin 38 19 8 12 2 79 

Sprinkler Systems 

o Hand Move 31 15 8 12 6 72 

o Solid Set 35 19 8 12 2 76 

o Center Pivot 30 19 8 12 2 71 

o Linear Move 35 19 8 12 2 76 

o Travel Trickle 35 19 8 12 2 76 

Trickle/Drip Systems 

o Surface Trickle 35 21 8 12 2 78 

o Subsurface Trickle 35 21 8 12 2 78 



7-27 



Table 7.7, continued 



Alternative 



Technical Economic Environ- Lega 1/In3ti- 
Feasi- Feasi- mental tutional Social Total 
bili ty bi 1 i ty Impact Constraints Constraints Ranking 2 / 



DRAINAGE WATER REUSE 

o Reuse with Blending 

o Reuse without Blending 

o Growth Stage Application 

o Subsurface Irrigation 

CROP MANAGEMENT 

o Increased Plant Density 

o Variable Spacing 

o Transplanting 

o Early Plant Date 

o Water Efficient Crops 

o Salt/Boron Tolerant Crops 

o Agroforestry 

o Fallowing 

SOIL AND SUBSURFACE DRAINAGE 
MANAGEMENT 

o Land Leveling and Grading 

o Deep Tillage 

o Organic Matter Incorp, 

o Drainage System Control 

ON-FARM STORAGE/TREATMENT/DISPOSAL OF 
DRAINAGE WATER 



28 


24 


4 


28 


26 


4 


20 


24 


4 


20 


33 


8 



23 


29 


8 


23 


29 


8 


19 


15 


8 


32 


33 


8 


35 


33 


8 


30 


33 


8 


32 


24 


8 


42 


25 


8 



36 


19 


8 


27 


21 


8 


25 


25 


8 


20 


22 


12 



12 

12 
12 
12 



12 
12 
12 
8 
12 
12 
12 
12 



12 
12 
12 
12 



72 

74 
64 
77 



76 
76 
60 
85 
92 
87 
80 
89 



79 
72 
74 
70 



Storage/Evaporation Ponds 
Immobilization of Se 
Bio-Accumulation of Se 



36 


22 


8 


14 


20 


4 


14 


20 


4 



78 
50 

50 



\_/ See Tables 7.2, 7.3, 7.4, 7.5 and 7.6 for rankings of each category. 
2^/ Total possible numerical ranking is 105. 



7-28 



TABLE 7.8 

OVERALL FEASIBILITY, AND PRIMARY LIMITATIONS OF 

ON-FARM MANAGEMENT ALTERNATIVES 



Alternative 



Overall 
Feasi- 
bility 1/ Primary Limiting Factors 



Extent Used 
in 
Project Area 
(H/M/L) 



IRRIGATION WATER CONSERVATION 



On-Farm Conveyance System 

Ditch S Canal Linings 

o Bentonite 

o Chemical Sealants 

o Membrane Linings 

o Concrete 
Pipel ines 

o Concrete 

o Metal 



L Life expectancy; limited area 

VL Life expectancy; limited area 

VL Life Expectancy; limited area 

M Installation cost; limited area 

H Installation cost; limited area 

H Installation cost; limited area 



Irrigation Management 

Water Control 

o Siphons and Tubes M 

o Surge-Flow H 

o Cablegation L 

Water Measurement 

oWeirs/Flumes M 

o Propeller-type VH 

o Pitot Tube VH 

Water Application 
Surface Systems 

o Shortening Run Lengths M 

o Return Flow Systems M 
o Volumetric Water Application M 
Sprinkler Systems 

o Increase Overlap H 

o Alternate Sets H 

o Avoid Windy Periods H 



Irrigation Scheduling 

Soil Moisture Deficit 
o Feel Method 
o Tensiometer 
o Gypsum Bock 
o Neutron Probe 
o Time Domain Ref lectometry 
o Leaf Water Potential 
o Canopy Temperature 

Water Budget 

o Reducing Pre-irrigat ion 
o Irrigation Management 
Programs 



Irrigation Methods \_l 

Surface Systems 
o Level Basin 

o Surface-drained Level Basin 
Sprinkler Systems 
o Hand Move 
o Solid Set 
o Center Pivot 

o Linear Move 
o Travel Trickle 
Trickle/Drip Systems 
o Surface Trickle 
o Subsurface Trickle 



H 

M 

L 
M 
L 

H 
H 

M 

M 



Limited effectiveness; high 

operation cost 
Installation cost; piped delivery 
Installation cost; piped delivery 

Installation cost 
Need piped delivery 
Need piped delivery 



Installation cost; increased 

field operations 
Installation cost 
Experimental; need return flow 

Installation cost 

None 

Water availability 



Limited effectiveness 



maintenance cost 
maintenance cost 
operation cost 



Installation & 

Installation S 

Installation S 

Experimental 

None 

None 



Water allocation policy 
Operation cost 



Installation cost, 

field leveling 
Installation cost. 



<2% slope, 
field leveling 



Operating cost 

Installation S maintenance cost 

Poor application uniformity, high 

installation cost, erosion 
Installation S maintenance cost 
Installation & maintenance cost 

Installation cost; short life 
Installation cost; short life 



7-29 



Table 7.8, Continued 



Alternative 



Overall 
Feasi- 
bility 1/ 



Primary Limiting Factors 



Bxtent Used 
in 
Project Area 
(H/M/L) 



DRAINAGE HATER REUSE 



o Reuse with Blending 

o Reuse without Blending 
o Growth Stage Application 

o Subsurface Irrigation 

CROP MANAGEMENT 

o Increased Plant Density 

o Variable Spacing 

o Transplanting 

o Early Plant Date 

o Water Efficient Crops 

o Salt/Boron Tolerant Crops 

o Agroforestry 

o Fallowing 

SOIL AND SOBSORFACE DRAINAGE 
MANAGEMENT 

o Land Leveling and Grading 

o Deep Tillage 

o Organic Matter Incorp. 

o Drainage System Control 

ON-FARM STORAGE/TREATMENT/DISPOSAL OF 
DRAINAGE WATER 

2/ 
o Storage/Evaporation Ponds 
o Immobilization of Se 
o Bio-Accumulation of Se 



L Requires return system; 

exper imen tal 
L Requires return system: 
VL Requires return system: 

experimental 
M Experimental 



M Equipment limitations 

M Equipment limitations 

VL High cost; equipment limitations 

M Disease 

H Lower value crop 

H Lower value crop 

M Installation cost 

H Fixed land and equipment costs 



M Operation cost 

L Operation cost 

L Climate 

L Experimental 



M Installation cost; regulations 

VL Cost: experimental 

VL Cost: experimental; disposal 



1/ Based on overall rankings from Table 7.7: Very high ( VH ) 96-105: High (86-95); 
Moderate (M) 76-85; Low (L) 66-75; and Very low { VL ) < 65. 



2_/ Overall feasibility assumes that Class 1 criteria from Subchapter 15 do not apply, 
criteria apply, then overall feasibility is very low. 



If 



7-30 



economics dictate on-farm management decisions within the 
constraints of rules and regulations established by federal/ state; 
and local agencies. 

Farmers manage their operations to maximize returns, applying 
rational decisions to address the requirements of the range of 
conditions that exist under their particular circumstances. Table 
7.9 summarizes examples of factors which may affect the amount of 
irrigation water application. Table 7.10 summarizes examples of 
factors which affect drainage water volume. These summaries are not 
provided as exhaustive lists of factors but as examples of the 
complexity of the issue. The lists in Table 7.9 and 7.10 are used as 
the basis to identify examples of factors which affect the decision 
making processes related to implementing management alternatives 
(Table 7.11). 

Factors which influence the decision making process can be separated 
into three general categories: 1) fixed; 2) external; and 3) 
internal. Fixed factors are those which dictate farm management 
decisions over which the farmer has very little control. Examples 
of fixed factors include elements such as climate, soil conditions, 
and topography. External factors are largely regulatory or 
institutional over which the farmer has very little control but that 
can be modified by others through changes in laws and regulations. 
Internal factors are those over which the farmer can exercise some 
degree of control since they are based on management decisions and 
financial capability. In the absence of regulatory changes, 
internal factors are the only elements that a farmer can modify to 
reduce his subsurface drainage water flows. Based on the matrix 
evaluation, a number of management alternatives appear feasible for 
reducing subsurface drainage water flows. A farmer's decision will 
thus be based on a systems approach analysis by which management 
alternatives can be evaluated to determine their effectiveness under 
his particular set of internal factors. This approach is necessary 
because even though the technical feasibility of many management 
alternatives is known, there are many different sets of economic data 
atypical to selected farming operations. 

An alternative not discussed, which is probably more related to 
institutional factors, is to take no action. Under this scenario, 
the state and federal governments would not develop programs 
necessary to assist the funding to implement on-farm management 
alternatives. As a result, many growers would be forced to use 
existing operations/facilities by combinations of external and 
internal factors. With the continuation of existing conditions, 
drainage conditions on downslope lands would continue to degrade 
while upslope lands would likely remain unaffected. Growers with 
marginal operations would be unable to finance improvements and 
would continue using present crop production methods. Eventually, 
land with drainage problems would become uneconomic to farm and would 
revert ot the appropriate financial institution, probably as a 
result of foreclosure action. The ability of the land to produce 



7- 31 



TABLE 7.9 
EXAMPLE OF FACTORS WHICH AFFECT THE AMOUNT OF 
IRRIGATION WATER APPLICATION 



Factors 



District water service contract 

Source 

Quantity of water available 

Type 

Cost of water 

Cropping pattern/average ET 

Climatic factors/average ET 

Soil conditions 

Location of land (upslope or downslope ) 

Slope 

Distribution system losses 

Method of application 

Depth to groundwater 

Quality of applied water 

Drainage/salt management problem 

Opportunity for irrigation supply resale 

Availability of drainage disposal method 

Availability of irrigation scheduling information 

Cost of drainage disposal 

Availability of investment funds/loans 

State/local drainage discharge limitation 

Knowledge of irrigation technology 

Availability of groundwater water rights water to 

supplement irrigation supply 
Flexibility of farm management 
Debt/equity as it affects investment & temporary reduced 

production 
Crop subsidies 

Reuse of drainage water - subsurface/ surface 
Contaminants within drainage water 
Use of shallow groundwater as irrigation supply 
Fallow (all or portion of a farm) 
Crop marketing decisions 
Water marketing 



7-32 



agricultural revenues would then govern its value and it could be 
resold at a price that allows someone to develop a management plan 
needed to control the subsurface drainage problem. The no action 
approach would result in financial losses for both farmers and 
lending institutions and would not lead to the resolution of existing 
subsurface drainage problems since it would not impact upslope 
growers. 

TABLE 7.10 
EXAMPLE OF FACTORS WHICH AFFECT DRAINAGE WATER VOLUME 



Examples 



Irrigation efficiency 

Use of salt tolerant crops - trees/ field crops 

Impact of upslope irrigation 

Cost of drainage disposal 

State/local drainage discharge limitations 

Reuse of drainage water 



The key to the decision making process is the fixed and variable cost 
of the management alternative in relation to the magnitude of 
existing costs. Variable costs can change on a seasonal basis while 
fixed costs are incurred at the same level each year regardless of the 
amount of use. The stage of amortization or depreciation of 
existing equipment and facilities will have a significant impact on a 
farmer's decision to implement management alternatives. Farmers 
will likely continue existing management conditions if equipment and 
facilities are not fully amortized or depreciated. The viability of 
a farming operation is a significant concern not just from the profit 
approach but also from a vitality standpoint. The decision to 
implement management alternatives will probably be based on an 
alternative futures analysis and farmers will resist changes unless 
they perceive they will be better off by making the changes. 

Farmers in drainage problem areas are interested in implementing 
feasible management alternatives as a means of mitigating drainage 
problems. At some farms/ improved irrigation practices and water 
conservation measures have been installed. However, it is 
irrational for upslope farmers, who have no incentive to change, to 
operate differently. These farmers will continue to contribute to 
subsurface drainage problems until they are forced to change by some 

7- 33 



TABLE 7.11 
EXAMPLE OF FACTORS AFFECTING FARMER DECISIONS TO 
IMPLEMENT MANAGEMENT ALTERNATIVES 



Fixed 



External 



Internal 



Climatic factors/ 
average ET 

Soil condition 

Location of land 
{ up or down slope ) 

Slope 

Depth to groundwater 

Quality of applied 
water 

Drainage/salt manage- 
ment problem/contami- 
nants within drainage 
water 

Use of shallow 
groundwater as 
irrigation supply 



District water supply 
contract-source /quantity 
of water available/ type 

Cost of water 



Cropping pattern/ 
avg. ET 

Distribution system 
losses 



Quality of applied water Method of applic. 



Opportunity for irrigation 
supply resale 

Avail. of drainage diposal 
method/Cost of drainage 
disposal/state/local 
drainage discharge limi- 
tations. 

Avail. of irrigation 
scheduling information 

Avail, of investment 
funds/loans 

Impact of upslope irrig. 

Crop subsidies 

State/federal govern- 
ment programs to provide 
economic incentives 



Drainage/salt mngmnt. 
problem/Contaminants 
within drainage water 

Avail. of drainage dis- 
posal method 

Avail. of irrig. sched. 

information 

(CIMIS type letter) 

Avail. of investment 
funds/loans/debt/equity 
as it affects invest- 
ment & temp, reduced 
production 

Knowledge of irriga- 
tion technology 

Avail, of grndwtr. 
resources to supple- 
ment irrig. supply 

Ability of farm 
mngt.to implement 
different practices 

Reuse of drainage 
water/ sub & 
surface 

Use of shallow 
grdwtr.as irriga. 
supply 

Crop marketing 
decisions 



7- 34 



regulation or economic incentive/disincentive. The economic 
incentive could be structured to allow these individuals to make 
more money. The economic disincentives would facilitate changes 
required to reduce losses. 

Simplistically , it would seem that an increase in the cost of 
irrigation water would provide ample incentive to conserve 
irrigation water thereby improving drainage conditions. However, 
since the cost of water is generally less than ten percent of total 
annual production costs, significant increases would be needed to 
reduce use. Further, farmers already conserving water and those in 
areas not contributing to the drainage problem would be penalized. 
This illustrates the difficulty associated with reducing drainage 
water flows by regulatory modifications. The ripple effect may be 
harmful to others. 

As system approaches are developed by individual farmers to 
implement management alternatives that address their conditions, it 
seems that some type of farm or regional treatment/disposal facility 
will be needed to dispose of brine and/or solids. This is not to 
suggest that farm evaporation ponds are a feasible disposal method, 
but this is one approach over which the farmer retains some control. 
On- and off-farm drainage water disposal alternatives need to be 
evaluated to determine long term effects on farm viability. 



7- 35 



SECTION 8 
FIELD/LABORATORY RESEARCH RECOMMENDATIONS 



8 . 1 GENERAL 

Throughout the development of this report it became obvious that in 
certain areas there was a shortage of information needed to totally 
evaluate the numerous on-farm alternative management practices 
identified. The technical aspects of management alternatives are 
generally well covered in the published and unpublished literature 
by University and government research organizations. However, 
these organizations often do not address the economic, 
environmental, institutional, and social impacts entailed in 
implementing new or improved management practices. Published 
cost/benefit data needed to evaluate the feasibility of on-farm 
management practices have not been related to the range of conditions 
found in the western San Joaquin Valley. 

Institutional constraints to implementing on-farm management 
practices are not generally understood by the public. For example, 
sophisticated irrigation scheduling programs may be severely 
compromised by inflexible water delivery systems. The impact of 
certain alternative management practices on air quality, water 
quality, and wildlife has not been fully evaluated. The social 
impact of alternative management practices, especially with regard 
to changes in labor requirements and economic benefits to the 
community, is not clearly known. 

8.2 RESEARCH APPROACH 

Research on alternative management practices needs to be conducted 
cooperatively with an existing farming operation(s) to address the 
effects of implementing appropriate technologies as evaluated with 
respect to all crop production operations. The direct costs and 
benefits associated with implementing alternative management 
practices could then be evaluated with respect to characteristics of 
the particular farming operation. The practical aspects of various 
management alternatives could also be compared with existing 
management approaches based on the knowledge and technical expertise 
of farm managers and field workers. 

An in-depth inventory of the resources located in the farm management 
unit is key for correlation and quantification of demonstration 
results. The soil resource which provides the pathway for 
hydrologic and chemical flows into and out of the farm area needs to 
be inventoried and monitored. Monitoring of applied water 
quantities, water distribution, contribution to shallow water 
tables from irrigation, water table depths, and drainage flows into 
and out of the unit will be needed. Monitoring of salinity and 
potentially toxic constituents of irrigation water, drainage water, 

8- 1 



and the soil will be needed. Monitoring of the unit in this fashion 
would provide the controls needed for effective projection of 
demonstration results. 

The integrative effects of using an on-farm management systems 
approach (Section 7.5) in reducing subsurface drainage water flow 
need to be quantified by the research program. In addition, 
questions need to be addressed relative to the most economical 
management system. 

The initial research/demonstration approach would focus on 
alternatives that offer a potential for rapid implementation to 
minimize drainage problems. These practices would be demonstrated 
and presented to local growers, thus providing them with feasible 
management alternatives that will begin to improve drainage 
problems. The second approach would evaluate technologies that are 
feasible to use, but further information to determine economic 
and/or environmental impacts is needed. The third area of emphasis 
would focus on those management alternatives that are apparently 
feasible but technical data on implementation are lacking. In 
addition to the above, economic research comparing existing 
technologies with new technologies will be required. Finally, a 
mechanism (model) for integrating and evaluating the most likely 
combinations of practices, their effectiveness in providing a 
solution, economic benefits and costs, and environmental and social 
considerations associated with their use is needed. 

8.3 RECOMMENDATIONS FOR FURTHER RESEARCH 

Evaluations of various on-farm management alternatives to reduce 
drainage flows or improve drainage water quality have revealed 
numerous management alternatives that may have practical 
application. Those alternatives that appear promising but which 
need further study with respect to their technical feasibility, 
economic costs/benefits, and environmental impact are summarized in 
this section. Considering the research approach described in 
Section 8.2, the following prioritized recommendations for further 
research are discussed under three major areas of emphasis: 1) 
Immediate Research Needs; 2) Intermediate Research Needs; and 3) 
Extended Research Needs. 

8.3.1 Immediate Research Needs 

Immediate research needs address those alternatives that could offer 
rapid improvement of subsurface drainage conditions but additional 
data (primarily economic) and grower education are needed. 
Management alternatives that should be evaluated include: 

o Reduce Pre-ir r igat ion 

Evaluate the amount and timing of pre-ir r igation with respect to 
the seasonal crop water requirement and cost. The effect of 

8- 2 



different institutional constraints in effecting a reduction of 
pre-irrigation also needs to be evaluated and an education 
process developed. 

o Technologies for Measuring Plant Moisture Stress 

The practicality and cost of new techniques for monitoring plant 
stress for irrigation scheduling purposes need to be further 
explored. Such techniques include infrared thermometry, leaf" 
water potential measurements, and time domain ref lectometry . 
Data need to be developed to demonstrate the cost effectiveness of 
different irrigation scheduling approaches as compared to 
existing management techniques. 

o Water Measurement and Control 

Evaluate the potential for improved irrigation efficiencies 
through use of water measurement and control devices. 
Cooperation with the Mobile Agricultural Water Conservation 
Laboratory is recommended. 

o Improve Existing Flood/Furrow Irrigation Systems 

Evaluate the effect of proper design to reduce surface irrigation 
run length, furrow dimensions, water flow, etc. on irrigation 
approach and basic cultural operations. Cost data need to be 
developed to evaluate the benefits from design/operational 
improvements against existing conditions. These data should be 
developed in sufficient detail for future evaluations/compar- 
isons of properly designed flood/furrow irrigation systems with 
automated drip/sprinkler systems. 

o Develop approaches to disseminate research results and educate 
growers in the implementation and management of feasible 
alternatives . 

8.3.2 Intermediate Research Needs 

Intermediate research needs address those alternatives that appear 
to offer a feasible technical solution to the drainage problems, but 
additional technical, economic, and grower education are required to 
provide data needed to make implementation decisions. Intermediate 
research should address the following: 

o Surge Irrigation and Cablegation 

Evaluate the technical management approaches, cost and benefits 
of these irrigation system alternatives compared to traditional 
surface irrigation practices. 



i- 3 



o Level Basin Irrigation 

This technology is potentially the most efficient surface 
irrigation method that does not require extensive technological 
expertise and needs to be reevaluated in the San Joaquin Valley. 
Evaluate this irrigation method in areas with cracking soils with 
variable water run lengths. Costs of installing and operating 
this system need to be evaluated in relation to the existing cost 
of conventional flood/furrow irrigation systems. 

o Linear Move Irrigation System 

Evaluate the costs of installing, operating and maintaining these 
systems compared to benefits and relation to existing 
flood/furrow irrigation system costs. Develop data to compare 
linear move system cost against other automated sprinkler 
systems . 

o Traveling-Trickle Irrigation System 

This system combines the advantages of a linear move system with 
that of low pressure trickle irrigation systems for use in row 
crops. Evaluate this innovative system and determine cost of 
installation, operation and maintenance, and benefits. Evaluate 
costs and returns against existing and other potential irrigation 
systems/methods. 

o Subsurface Trickle (Drip) Irrigation 

Evaluate the technology for trickle irrigating row crops without 
repeated placement and removal of surface trickle systems. 
Research operation and maintenance and costs and benefits for the 
range of soils and crops that occur in the project area. Evaluate 
the costs and benefits in relation to existing and other potential 
irrigation systems/methods. 

o Reuse Drainage Water for Irrigation 

Evaluate the advantages and disadvantages of irrigating with 
saline drainage water over a longer time period in order to 
determine effects of increasing soil salinity and boron levels on 
plant response. Determine the costs and benefits associated 
with implementation, operation, and management of this system. 

o Drainage Water Recovery Systems 

Compare relative costs, technical requirements, and environ- 
mental impacts of blending saline irrigation waters with fresh 
water and irrigation with drainage water without blending. 



8- 4 



o Variable Row Crop Spacing 

Variable row spacing is a cultural practice used in west Texas to 
improve the efficiency of cotton irrigation. To our knowledge, 
its application in the San Joaquin Valley huS not been tested. 
Evaluate variable row spacing using existing flood/furrow 
irrigation systems and compare with properly designed and 
operated flood/furrow systems. 

8.3.3 Extended Research Needs 

Extended research needs should focus on alternative practices whose 
technical and economic aspects are in question and need further 
research. Extended research should address the following: 

o Surface-drained Level Basin 

The surface-drained level basin is a recent variation of level 
basin irrigation technology. Instead of allowing irrigation 
water ponding on the field, water is allowed to drain from the 
field back into the head ditch for reuse. This method of level 
basin irrigation is well suited to sloping lands and has not been 
tested in California. The costs and benefits of this irrigation 
method need to be determined along with its adaptability to 
project area soil and topographic conditions. 

o Subsurface Drainage System Design and Management 

Evaluate the design criteria for drainage systems with respect to 
designing for minimum drainage flow, or maximum allowable 
midpoint water table depth without impairing crop yield. The 
design should allow management of groundwater elevation to allow 
the possible contribution of shallow groundwater to the crop 
water requirement. Where drainage systems exist, the technical 
feasibility of controlling drainage outflows as a means of 
controlling water table depths and excess drainage needs to be 
investigated. A cost analysis should be performed to evaluate 
the benefits of modified drainage designs in comparison to 
existing drainage design approaches. 

o On-Farm Storage/Evaporation Ponds 

Investigate the technology and costs of building on-farm 
evaporation ponds based on various design criteria. This is 
important in order to balance the costs of improved irrigation 
management technology to reduce drainage flows against the costs 
of building different sizes and classes of storage/evaporation 
ponds . 



!- 5 



o Transplanting 

Transplanting crops from the nursery to the field has been 
suggested as a method to reduce the need for pre-ir r igat ion . The 
technology to mechanically plant row crops typically grown in the 
western San Joaquin Valley has not been perfected. Although used 
for selected vegetable crops, transplanting has been too 
expensive to justify for row crops. This needs to be confirmed. 

o Precipitation and Adsorbtion of Selenium 

The technology of precipitating or adsorbing selenium and other 
potentially toxic trace elements within the soil can be 
considered a water treatment or source control process. The cost 
and effectiveness of attempting biologically mediated reduction 
and adsorption of selenium in the soil or drain lines by injection 
of methanol or other organics need to be investigated to determine 
efficacy and cost. 

o Agroforestry 

The concept of agroforestry is not new in California as attested 
by the remnant groves of southern Blue Gum ( Eucalyptus globulus ) 
found scattered throughout California's agricultural regions. 
The renewed interest in growing trees is based on their potential 
to be irrigated with saline water, to grow as a phreatophy te , and 
to provide an alternative fuel supply. Growing salt-tolerant 
phreatophytic tree species with high biomass production can 
potentially be used to draw down the water table in drainage 
problem areas in the western San Joaquin Valley and reduce the 
volume of subsurface drainage. Research needs to be performed 
to: 1) evaluate the evapotranspiration potential for various 
tree species at different growth stages under various 
environmental constraints, particularly waterlogged soils, soil 
salinity, and specific element toxicities (B, Na , CI, etc.) or 
deficiencies (Fe, Zn, etc.); 2) determine the contribution of the 
groundwater to the trees total water requirement; 3) evaluate the 
time trees can grow before succumbing to salt injury from an 
increasing buildup of salts in the soil profile and shallow 
groundwater; 4) evaluate systems approaches to determine how 
agroforestry can be integrated with other on-farm management 
practices; and 5) determine costs and benefits of agroforestry on 
the west side of the San Joaquin Valley. 

o Selection of Crops for Salt/Boron Tolerance 

Current technical research in this field is generally being 
covered adequately by university and government researchers; 
however, the costs and benefits of growing these crops need to be 
determined . 



8- 6 



o Volumetric Water Application for Furrow and Border Check 
Irrigation Systems 

The technical feasibility of continuous tailwater return to the 
head of the furrow where the water originated needs to be 
evaluated with respect to achievable irrigation efficiencies, 
costs, and benefits. 

o Irrigation Using Shallow Water Tables 

Managing the water table elevation to provide subirr igat ion may 
be an effective method of reducing drainage volume. This may be 
achieved by modifying existing subsurface drainage facilities 
and by developing new design/installation criteria and 
practices. VJork needs to be conducted to determine the 
feasibility and cost of implementing this highly technical 
management practice. Farming units with existing subsurface 
drainage systems are required in order to study the costs and 
benefits of this operation. 

o Bio-accumulation 

Evaluate the degree that various plant species concentrate 

selenium and other potentially toxic trace elements in their 

tissues. Evaluate costs and benefits and determine methods of 

disposal or potential markets, if applicable. 

8.3.4 Summary 

To date, an intensive coordinated research effort required to 
address alternative management approaches has not been implemented. 
A major constraint seems to be a lack of overall understanding of the 
drainage problem and potential solutions. Further, the objective 
of existing research has not addressed the need to provide technical 
and economic information needed to make rational decisions. The 
method of disseminating this information and educating the farmer is 
an important consideration and efforts need to be greatly expanded. 
The coordination of research efforts should be performed by a 
federal/state agency or task force with practical knowledge of farm 
operations and the complex technical issues involved. The work 
should be contracted to agencies and/or private firms with 
demonstrated capability of performing the required research. It is 
anticipated that a multi-discipline approach will be needed 
including input from the private sector. The effect of particular 
alternative management practices or management systems could then be 
better evaluated with respect to the technical feasibility of 
implementation and actual cost and benefit to a particular farming 
operation . 

The alternatives discussed above have the potential of significantly 
impacting the drainage problems currently facing growers on the west 
side of the San Joaquin Valley. Integrating practices to achieve an 

8- 7 



effective management system and grower education is key to realizing 
this overall potential. New areas of research on reducing 
subsurface drainage flow will undoubtedly continue to develop from 
the current trials. On-going evaluation, integration, and 
demonstration programs should be implemented that would provide 
public education and involvement and assistance to growers in 
controlling subsurface drainage related problems. 



!- 8 



SECTION 9 
FINDINGS AND CONCLUSIONS 



9.1 GENERAL 

The technical information for management alternatives has been 
largely developed by the University of California, Agricultural 
Research Service, and other research groups. However, these 
research groups, including the University of California, could 
effect greater success by: 1) redirecting research programs to 
solve production problems as perceived by growers; 2) providing cost 
information to aid grower decision making; and 3) developing 
effective educational programs needed to disseminate information. 
Also, growers and water districts feel they have been abandoned by 
the state and federal governments and left to solve drainage problems 
without assistance. The state and federal governments are 
perceived by some to be unresponsive to the problem and as failing to 
provide a cohesive approach to solving the problems. Water 
districts and growers in the San Luis Service Area are frustrated in 
their belief that agencies responsible for providing drainage 
according to contractual agreement are reneging. Slow response to 
the problem is particularly vexing to growers in drainage problem 
areas who need rapid solutions because they foresee being forced out 
of business in five years or less because of drainage problems. 

Another problem is the growers' perception of conditions. Growers in 
drainage problem areas need to improve subsurface drainage 
conditions to maintain productive farms, but upslope growers 
contribute to the drainage problems but are not equally committed to 
solving these problems. Therefore, one of the more difficult 
aspects of the problem is the development of an equitable and 
acceptable method to share the cost of corrective measures among 
those contributing to the drainage problems. Education programs 
will aid this effort as well as help growers make sound farm 
management decisions. 

Findings and conclusions are presented in the following sub- 
sections. General findings and conclusions are followed by more 
specific conclusions. 

9.1.1 General Findings and Conclusions 

o Agricultural lands on the west side of the San Joaquin Valley are 
being increasingly impacted by the rise of saline shallow 
groundwaters into the crop root zone. 

o Data are insufficient to reliably estimate the costs and 
benefits of management alternatives and their specific impacts 
on subsurface drainage water volumes and quality. 



9- 1 



o The drainage problem is attributable largely to the importation 
of irrigation water from state and federal water projects which 
have expanded irrigated farming without providing adequate 
means to remove and dispose of drainage water. 

o Irrigation efficiencies are highly variable depending primarily 
on the crop grown, irrigation management practices, and whether 
or not there is a high water table problem that contributes to 
crop ET. 

o The relative contributions of downslope and upslope lands under 
different cropping patterns and irrigation management practices 
to drainage problems are very poorly understood. 

o Reducing agricultural drainage flows by improving irrigation 
efficiency could eventually cause increasing salinity of the 
soil profile unless periodic salt leaching is performed. 
Without leaching, crop yield will decrease or more salt tolerant 
crops, which are generally less profitable, will need to be 
grown . 

o Most subsurface waters are highly saline and may only be suitable 
for reuse on the most salt- and boron-tolerant crops. Some of 
these waters have also been observed to contain elevated levels 
of trace elements such as selenium. 

o In areas impacted by a rising water table, evaporation ponds 
and/or other means of disposal will eventually be needed to 
maintain continued crop production. 

o Incentives for improving irrigation efficiency and reducing 
percolation losses will be stronger in those areas where the rise 
of the water table into the crop rooting zone is imminent. 

o Farmers in areas without immediate drainage problems, although 
contributing to drainage problems in other areas, are not 
motivated to improve irrigation efficiency and thus reduce 
percolation . 

o A solution to the drainage problem will entail a combination of 
both on- and off-farm management practices. It may also be 
necessary for the state and federal governments to directly or 
indirectly reevaluate laws and regulations influencing farm 
management . 

o To develop the best selection of management strategies given 
existing technical, economic, institutional, environmental, and 
social constraints, optimization analytical methods using 
computer models may be necessary. 



9- 2 



9.1.2 Findings and Conclusions on Management Practices 

o Irrigation management practices that are easy to implement, 
relatively inexpensive, and that can be implemented rapidly 
include : 

Pre-irr igation reduction. 

Irrigation scheduling (performed by grower, water district, 
cooperative extension, or professional consultant). 

Water control and measurement (implementation is easy for 
piped systems but the critical need is for measurement in 
open conveyance facilities) . 

Shortening irrigation runs. 

o Irrigation management practices demonstrated to be economically 
and technically feasible outside California but that have not 
been fully demonstrated in California include: 

Level-basin irrigation. 

Surge irrigation. 

o Irrigation and other management practices that need further 
evaluation to define technical and economic feasibility 
include : 

Cablegation. 

Surface-drained level-basin. 

Volumetric water application for furrow and border-check, 
irrigation systems (including tailwater return system). 

Travel-trickle irrigation. 

Subsurface trickle irrigation for row crops. 

Saline water reuse for irrigation. 

Variable row spacing of crops. 

- Shallow groundwater table management to supplement 
irrigation water supply (including subsurface drains). 

- Design and management of on-farm storage and evaporation 
ponds without significant risk to wildlife resources. 

Row crop transplanting. 



9- 3 



Selection of alternative crops for salt/boron tolerance. 

Control the source of selenium by reduction and 
precipitation . 

Inclusion of forestry crops (agrof orestry) in the normal 
cropping pattern. 

9.1.3 Findings and Conclusions on Technical Aspects and Costs 

o Most on-f arm management alternatives to reduce drainage flows or 
to improve drainage water quality are technically feasible. 

o The costs and benefits of implementing many on-farm management 
alternatives to reduce drainage flows are uncertain. 

o The cost of improving irrigation efficiency must be weighed 
against the benefits. Improving irrigation efficiency reduces 
but does not eliminate the drainage problem. 

o The cost of on-farm management practices to reduce subsurface 
drainage flows is uncertain, but it is expected to be less per 
volume of drainage water than treatment and/or disposal 
alternatives . 

o Growers outside drainage impacted areas will invest in 
technology to improve irrigation efficiency only if the overall 
profit margin can be increased regardless of water savings. 
However, growers within the drainage impacted areas will be 
motivated to improve operations to cope with the drainage 
problem and remain in business. Therefore, management 
alternatives may be implemented at increased costs in the 
drainage problem areas to insure continuing productivity. 

o The technical and cost suitability of various management 
practices, in the final analysis, depends on the circumstances 
of individual farm management units. 

9.1.4 Findings and Conclusions on Institutional Factors 

o Federal and state agencies and local water districts can 
encourage better management practices by changing water 
allocation, water marketing, and water pricing rules and 
regulations. For example, more flexible water delivery can 
achieve more effective irrigation scheduling. The ability of a 
grower or district to market conserved water will promote 
efficient irrigation. The present benefits of conserving water 
often do not offset conservation costs because of inexpensive 
irrigation water. 

o State water rights laws recognize water rights on the basis of 
the amount used. The threat of possible loss of water rights 



9- 4 



discourages improved irrigation efficiency and reduced water 

use . 

o Current federal and state policies and regulations limit 
interbasin exchanges of water or water marketing made available 
through water conservation. Water marketing and interbasin 
transfer of water could provide a profit motive to growers to 
improve irrigation efficiency to conserve marketable water. 

o The cost of storage/evaporation ponds for drainage water would 
be very expensive if the criteria for Class I ponds specified by 
the Toxic Pits Act are required. 

o Charging water contractors and farmers a flat, annual fee for 
water used in excess of on-farm needs encourages waste. 

o Irrigation efficiency can be more easily improved if the water 
supply to the farm is available on demand. The flexibility to 
deliver water on demand varies among water agencies. 

9.1.5 Findings and Conclusions on Environmental and Social 
Factors 

o Management practices to reduce drainage flows and improve 
drainage water quality may increase soil salinity which would 
have a detrimental effect on crop production. This potential 
impact can be avoided by providing the leaching requirement. 

o Concentrations of contaminants in on-farm evaporation ponds may 
in time increase to levels exceeding hazardous waste criteria 
specified in the Toxic Pits Act in which case significantly more 
stringent pond construction standards may be imposed. 

o Certain crops accumulate trace elements (contaminants such as 
selenium) and pose a food source hazard to the fish and wildlife 
food chain. These accumulated trace elements could also pose 
health hazards to the human population. 

o Certain management practices such as automated irrigation 
systems may reduce the required labor force. 

o Irrigation of soils containing trace element contaminants such 
as selenium will cause environmental concerns. 

9 . 2 RECOMMENDATIONS 

Recommendations based on the findings and conclusions of this report 
are grouped in three categories: 1) recommendations for on-farm 
management practices that would reduce subsurface drainage flows or 
improve drainage water quality; 2) recommendations for 
institutional changes that would encourage improved management 
practices; and 3) recommendations for research and demonstration to 

9- 5 



evaluate combinations of alternative management practices. 

9.2.1 Recommended On-farm Management Practices 

Shallow groundwater tables can be lowered by on-farm practices such 
as fallowing, seasonal cropping changes, agrof orestry , irrigation 
scheduling, etc. On-farm management practices could be immediate 
and extended practices. The immediate practices are those that do 
not require extensive technical expertise or financial investment. 
The extended practices are those that must be evaluated carefully 
because of more extensive technical requirements, high costs, or 
environmental constraints. Management practices are not univer- 
sally applicable and suitable for all farms. Recommendations must 
be weighed in light of the circumstances of the individual farm unit. 
Those management practices that need further study to evaluate their 
technical and economic feasibility are considered in a third 
category . 

Recommended immediate management practices which do not require 
extensive technical expertise or financial investment include: 

o Development of a grower education program. 

o Installation of water measurement and control devices. 

o Evaluation and implementation of irrigation management 
practices using principles demonstrated by the DWR Mobile 
Agricultural Water Laboratory. 

o Establishment of an irrigation scheduling program using methods 
recommended by the DWR Irrigation Management Program or by using 
professional irrigation scheduling services. 

o Pre-ir r igation on the basis of water required to bring the plant 
root zone to field capacity rather than on the amount of 
remaining water allotment. 

o Shorten furrow irrigation runs in fields with high infiltration 
rates or cracking soils. 

Recommended extended management practices that may require either a 
high level of technical expertise or a substantial capital 
investment (automated irrigation system costs may exceed $400/acre) 
which generally require professional advice before implementing 
include : 

o Installation of canals or pipes for on-farm conveyance 
facilities . 

o Level and grade fields using proper engineering design for 
surface irrigation methods. 



9- 6 



o Installation of tailwater and subsurface drainage water return 
systems . 

o Installation of automated surge flow systems for furrow 
irrigation where suitable. 

o Establishment of level-basin irrigation systems on suitable 
soils with appropriate field sizes. 

o Installation of a linear move irrigation system. 

o Construction of storage/evaporation ponds. 

Recommended research to evaluate the technical and economic 
feasibility of farm management alternatives includes: 

o Subsurface trickle irrigation systems for row crops. 

o Travel-trickle irrigation system. 

o Surface-drained level basin system on moderately sloped land. 

o Use of salt-tolerant trees to lower the water table and reduce 
subsurface drainage volume on lands with a high water table. 

9.2.2 Recommended Institutional Changes 

Recommended institutional changes that facilitate implementation of 
alternative on-farm management practices which would result in 
reduced drainage flows or improved drainage water quality include: 

o Provide long-term low interest loans to farmers through 
government agencies in order to finance physical improvements 
that would result in increased irrigation efficiency. 

o Provide research grants for developing technical and economic 
data for on-farm management practices needed to improve water 
conservation in drainage problem areas. 

o Allow the sale of contracted water by the original water district 
to a second party outside the district boundary. Monies from 
water sales could be used to partially finance the 
implementation of water conservation measures. 

o Relax restrictions on interbasin or CVP to SWP exchanges of 
contracted water where overall benefits to the regional economy 
and environment can be demonstrated. 

o Increase the price of water to irrigation districts. Revenues 
would be directed toward educational programs to improve 
irrigation efficiency and to finance other management practices 
needed to reduce subsurface drainage flows or to treat and 



9- 7 



dispose of drainage waters. 

o Develop a water price schedule to charge growers for wasted 
water. This approach would place an economic burden on those 
growers who apply irrigation water in excess of ET plus a 
reasonable leaching fraction and irrigation efficiency. 

o Adopt the Soil Conservation Plan currently being drafted by the 
California Department of Conservation. 

o Establish design and operation criteria for agricultural 
evaporation ponds. 

o Continue at the present level or, if possible, expand the DWR 
Mobile Agricultural Water Laboratory Program. 

o Provide incentives for using irrigation scheduling services. 

o Provide increased flexibility in the frequency, rate, and 
duration of water deliveries to the farm headgate. This will 
require a cooperative effort of the Department of Water 
Resources, the USER, and local water agencies. 

9.2.3 Recommendations for Further Research or Demonstration 
Projects 

Alternative management practices need to be evaluated with respect 
to their technical and economic feasibility in an existing farm 
operation. These operations could represent drainage problems in 
downslope areas and the contribution of upslope areas to the drainage 
problems. Monitoring water applications, runoff, water table 
depths, drainage flows, crop acreages, evapotranspirat ion , and deep 
and lateral seepages would have to be considered in order to evaluate 
the effect of various management practices or combinations of 
management practices on subsurface drainage. Farm budgets which 
consider all aspects of farm operations would be generated to 
determine the net profit or loss attributable to modified management 
practices or combinations thereof. 

Because of the complex hydrolog ic-economic interrelationships of 
various management alternatives as well as institutional, 
environmental, and social constraints to their implementation, 
computerized optimization analyses should be developed. This 
approach would require the development of theoretical consider- 
ations to facilitate testing the effects of various technical, 
economic, institutional, environmental, and social factors on the 
feasibility of implementing the various on-farm management 
practices in the context of existing on-farm management units. 



9- 8 



APPENDIX A 
BIBLIOGRAPHY 



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501. Wallace, L. T., and T. B. O'Connell. 1966. Survey of 
California water service organizations. Univ. of Calif. 
Div. of Agric. Sci., Giannini Foundation Series No. 66-4, 
July, 1966. 



A- 4 4 



502. Wallender, W. W. , D. W. Grimes, D. W. Henderson, and L. K. 
Stromberg. 1979. Estimating the contribution of a perched 
water table to the seasonal evapotranspirat ions of cotton. 
Agron. J. 71:1056-1060. 

503. Water Quality Committee of the Irrigation and Drainage 
Division. 1985. Report of task committee on water quality 
problems resulting from increasing irrigation efficiency. 
J. Irrig. Drain. Eng . 111( 3) : 191-198 . 

504. Watson, W. D., C. F. Nuckton, and R. E. Howitt. 1980. Crop 
production and water supply characteristics of Kern County. 
Davis: Univ. of Calif. Dept . of Agric. Economics. 
Information Series - Giannini Foundation of Agricultural 
Economics: 80-1 (Univ. of Calif. Div. of Agri. Sci. Bull. 
1895) . 

505. Weir, W. W. 1916. Preliminary report on Kearney Vineyard 
experimental drain, Fresno County, California. Univ. of 
California Agric. Expt. Sta. Bull. No, 273. 

506. Welch, D. G., Jr., and D. A. Granahan. 1985. Irrigation 
scheduling with the neutron probe, p. 146-153. In C. G. 
Keys, Jr., and T. J. Ward (eds.) Development and management 
aspects of irrigation and drainage systems. Proc. of the 
Spec. Conf. sponsored by the Irrig. Drain. Div., ASCE, San 
Antonio, TX . July 17-19, 1985. 

507. West, D. W., and L. E. Francois. 1982. Effects of salinity 
on germination, growth and yield of Cowpea. Irrig. Sci. 
3:169-175. 

508. Westcot, D. W. , and R. S. Ayers. 1985. Irrigation water 
quality. Chap 3. In G. S. Pettygrove and T. Asano (eds.) 
Irrigation with municipal wastewater - a guidance manaual. 
Lewis Publishers, Inc. Chelsea, MI. 

509. Westlands Water District. 1981. Water conservation and 
management handbook. Westlands Water Dist., Fresno, CA. 

510. Wierenga, P. J. 1979. Soil salinity and cotton yields as 
affected by surface and trickle irrigation. New Mexico 
Water Resources Research Institute, No. 106, Las Cruces, 
NM. 

511. Wierenga, P. J., and M. H. Saddiq. 1985. Optimum soil water 
tension for trickle irrigated chile peppers, p. 193-197. In 
Drip/trickle irrigation in action. Vol. I. Proc.^Third 
International Drip/Trickle Irrigation Congress, Fresno, CA, 
Nov. 18-21, 1985. (ASAE Pub. 10-85) Amer . Soc . Agric. Eng., 
St. Joseph, MI. 

512. Wilcox, L. V. 1960. Boron injury to plants. U. S. Dept. 
Agric. Inf. Bull. No. 211, 7p. 

A- 4 5 



513. Wilcox, L. V. 1963. Salt balance and leaching requirements 
of irrigated lands. U. S. Dept . Agric. Tech. Bull. 1290, 
23p. 

514. Willardson, L. S. 1985. Basin-wide impacts of irrigation 
efficiency. J. Irrig. Drain. Eng . Ill ( 3) : 241-246 . 

515. Willardson, L. S. and R. J. Wagenet. 1983. Basinwide 
impacts of irrigation efficiency, p. 522-529. In Borrelli, 
J., V. R. Hasfurther, and R. D. Burnam, Advances in 
irrigation and drainage: surviving external pressures. 
Proc. Spec. Conf. Irrig. Drain., ASCE , Jackson, WY , July 
20-22, 1983. 

516. Withers, B., and S. Vipond . 1980. Irrigation design and 
practice. Cornell Univ. Press, Ithica, New York. 

517. Woods, R. J., and J. H. Snyder. 1984. Inventory of water 
research in the University of California. Calif. Water 
Resources Center, June, 189 p. 

Epstein. 1982. Screening for salt 
an ecological approach, p. 559-564. Ir 
Biosaline research. Int'l. Workshop on 
2nd, La Paz, Mexico, Nov. 16-20, 1980. 



518. Wrona, A. F., and E. Epstein. 1982. Screening for 

tolerance in plants: an ecological approach, p. 559-564. In 
A. San Pietro (ed.) Bios. 
Biosaline Research, 2nd, 
Plenum Press, N.Y. 



519. Yaron, B., E. Danfors , and Y. Vaadia (eds.). 1973. Arid 
zone irrigation. Spr inger-Ver lag , Heidelberg and Berlin. 

520. Zazueta, F. S., A. G. Smajstrla, and D. S. Harrison. 1985. 
Microcomputer aided design and management of trickle 
irrigation systems, p. 433-438. In Drip/trickle irrigation 
in action. Vol I. Proc. Third International Drip/Trickle 
Irrigation Congress, Nov. 18-21, 1985, Fresno, CA. (ASAE 
Pub. 10-85) Amer. Soc. Agric. Eng., St. Joseph, MI. 



A- 46 



APPENDIX B 
KEYWORD INDEX 



KEYWORD INDEXi/ 

Subject: Crop Plants 

alfalfa: 31, 33, 58, 102, 125, 182, 209 

barley: 332 

citrus: 210 

corn: 40, 191, 208, 269, 294, 297, 318 

cotton: 17, 128, 145, 168, 170, 177, 178, 207, 218, 219, 273, 

303, 306, 309, 323, 327, 359, 370, 380, 390, 450, 451, 452, 
478, 502, 510 

crop: 2, 14, 27, 29, 43, 68, 74, 84, 87, 105, 122, 140, 143, 144, 

165, 201, 215, 229, 230, 246, 247, 268, 278, 281, 285, 290, 

292, 295, 296, 298, 334, 341, 356, 365, 366, 367, 369, 391, 

435, 446, 447, 466, 479, 485, 495, 498, 504, 

plant: 25, 26, 36, 40, 121, 169, 187, 212, 233, 243, 247, 252, 
248, 272, 286, 291, 293, 315, 320, 358, 367, 374, 424, 431, 
433, 497, 498, 512, 518, 

eucalypt: 175, 252, 315, 403, 433 

grain : 451 

grass : 62 , 362 

guayule: 319, 320 

Prosopis: 330, 331, 425 

mesquite: 223, 331, 330 

rice: 49, 220 

shrub: 324 

sugar beet: 328 

tree: 324, 325 

grape: 37, 38 

wheat: 105, 131 

salt cedar: 119, 120 



B- 1 



Subject: Economics 

economic: 49, 88, 151, 260, 264, 322, 431, 494 

economic analysis: 49 

economy: 305, 416 

cost: 155, 200, 371, 417, 418 

price: 49, 220 

Subject: Engineering 

eng ineer : 464 , 465 

design: 1, 7, 14, 52, 53, 73, 193, 217, 228, 267, 313, 369, 
377, 417, 418, 429, 434, 452, 516, 520 

drainage: 6, 14, 23, 29, 31, 45, 48, 52, 53, 54, 61, 71, 78, 
92, 93, 96, 108, 127, 139, 154, 164, 166, 167, 180, 181, 

182, 196, 201, 205, 206, 235, 236, 241, 255, 257, 263, 264, 

265, 266, 269, 282, 287, 302, 307, 310, 314, 333, 338, 339, 

351, 357, 369, 372, 378, 379, 380, 382, 388, 389, 390, 399, 

411, 412, 414, 416, 438, 443, 445, 448, 449, 455, 462, 472, 

480, 482, 484, 488, 490, 506, 515 

drainage design: 14, 52, 53, 369 

drainage problem: 23, 78, 96, 139, 255, 263, 264, 351, 416 

drainage management: 257, 263, 411, 412, 455 

drains: 180 

drainage systems: 14, 196, 257, 269, 310, 449, 455, 506 

tile drain : 3 57 

Subject: Experiments 

experiment: 143, 144, 215, 238, 245, 505 

evaluation: 60, 107, 134, 171, 220, 221, 235, 254, 283, 295, 
312, 415 



B- 2 



Subject: Institutions 

policies: 147 
institution: 55, 301 

Subject: Irrigation Management 



ir r igat 
30, 
58, 
107 
141 
163 
189 
210 
231 
257 
274 
310 
338 
358 
380 
395 
430 
465 
483 
515 



ion : 

31, 

60, 

, 108 

, 145 

, 164 

, 191 

, 211 

, 235 

, 258 

, 275 

, 311 

, 339 

, 359 

, 381 

, 396 

, 434 

, 466 

, 486 

, 516 



1, 3 
32, 37 
64, 66 

, 109, 

, 150, 

, 165, 

, 192, 

, 214, 

, 237, 

, 259, 

, 276, 

, 312, 

, 342, 

, 360, 

, 382, 

, 397, 

, 436, 

, 467, 

, 488, 

, 519, 



4, 
38 
68 
111 
151 
167 
193 
217 
241 
260 
277 
313 
346 
363 
383 
398 
444 
468 
491 
520 



5, 6, 
41, 
69, 
112, 
152, 
170, 
195, 
220, 
242, 
261, 
278, 
319, 
348, 
365, 
384, 
399, 
445, 
469, 
492, 



7, 

44, 

70, 
124 
153 
171 
196 
221 
244 
262 
281 
321 
349 
366 
385 
406 
449 
471 
493 



11, 14 
45, 46 
73, 84 
, 125, 
, 156, 
, 174, 
, 197, 
, 222, 
, 245, 
, 265, 
, 283, 
, 324, 
, 350, 
, 370, 
, 386, 
, 414, 
, 451, 
, 473, 
, 503, 



15 
47 
85 
128 
157 
180 
199 
225 
246 
266 
288 
328 
351 
371 
387 
419 
452 
474 
506 



16, 

48, 

87, 

129, 

158, 

182, 

201, 

226, 

248, 

267, 

289, 

332, 

353, 

372, 

388, 

421, 

455, 

475, 

508, 



17, 

52, 

102, 
133 
159 
185 
204 
227 
253 
268 
299 
333 
354 
376 
389 
423 
457 
476 
510 



18, 27 
54, 56 

104, 
, 134, 
, 161, 
, 187, 
, 205, 
, 228, 
, 254, 
, 269, 
, 300, 
, 334, 
, 355, 
, 377, 
, 390, 
, 427, 
, 458, 
, 478, 
, 511, 



, 28, 
, 57, 
106, 
135, 
162, 
188, 
209. 
229, 
256, 
270, 
303, 
337, 
356 
379 
392 
429 
464 
480 
514 



irrigation efficiency: 5, 52, 152, 231, 266, 342, 363, 381, 387, 
486, 493, 503, 514, 515 

irrigation management: 15, 16, 46, 68, 109, 156, 161, 162, 170, 
188, 204, 209, 210, 257, 259, 329, 299, 350, 376, 392, 423, 
430, 434, 455, 467, 491, 492 

irrigation systems: 1, 7, 15, 41, 69, 73, 106, 111, 112, 
128, 189, 193, 217, 228, 254, 267, 313, 354, 377, 434, 520 

runoff: 333, 484 

tailwater: 417, 41 

water control: 96 

water management: 68, 71, 135, 178, 182, 183, 288, 289, 299, 337, 
352, 434, 455, 456 



B- 3 



Subject: Irrigation Methods 

basin irrigation: 129, 153, 170, 270 

cablegation: 256 

border irrigation: 221 

furrow irrigation: 128, 465 

level basin: 125, 126 

sprinkler irrigation: 30, 66, 106 

subsurface: 174, 180, 181, 359, 443, 451 

surface irrigation: 41, 256 

surge flow irrigation: 42 

trickle irrigation: 17, 37, 68, 69, 124, 170, 171, 174, 300, 
350, 356, 359, 427, 451, 452, 510, 511, 520 

drip irrigation: 32, 156, 303, 324, 350, 366, 451, 452, 478 

Subject: Irrigation Scheduling 

consumptive use: 227 

crop water use: 14 

evaporation: 175, 176, 194, 300, 443 

transpiration: 119, 120, 121, 175, 318, 356, 444, 502 

scheduling: 4, 45, 47, 64, 84, 85, 87, 133, 151, 157, 158, 159, 
162, 187, 192, 195, 201, 225, 226, 229, 237, 261, 283, 288, 
300, 309, 355, 358, 360, 376, 506 

water conservation: 82, 90, 100, 115, 116, 117, 118, 122, 123, 
147, 196, 233, 237, 253, 301, 326, 366, 393, 432, 509 

water requirement: 73, 140, 227, 

water budget: 420 



B- 4 



Subject: Legal Considerations 

law: 55, 211, 277, 278, 486 
legal: 13 

Subject: Location 

Arizona: 49, 210, 452 

California: 12, 21, 34, 35, 55, 59, 61, 79, 80, 82, 86, 89, 90, 
96, 97, 98, 99, 101, 115, 117, 130, 137, 139, 147, 148, 166, 
171, 184, 200, 203, 208, 250, 251, 255, 280, 283, 288, 308, 
315, 330, 331, 345, 361, 362, 364, 373, 408, 414, 416, 425, 
430, 436, 478, 481, 501, 505, 517, 

Coachella Valley: 59, 373 

Colorado: 8, 47, 110, 211, 270, 399 

Grand Valley: 47, 500 

Imperial Valley: 61, 250, 342, 482 

San Joaquin: 15, 23, 34, 35, 51, 75, 76, 78, 84, 87, 88, 92, 93, 
94, 96, 109, 117, 130, 136, 166, 171, 208, 299, 307, 308, 
363, 364, 380, 408, 411, 412 

Texas: 323 

Utah: 46, 191 

Subject: Models 

model: 11, 88, 201, 281, 394, 485 
computer: 64, 162, 192, 225, 321, 520 

Subject: Plant Response 

crop growth: 29 

crop production: 246, 247, 278, 435, 446, 447, 479, 495, 504 

crop yield: 165, 201 

germination: 507 

plant growth: 286, 424 

B- 5 



plant response: 169 

root: 33, 37, 40, 58, 173, 286, 339, 340, 368, 498 

salt tolerance: 26, 27, 208, 223, 272, 273, 291, 293, 295, 296, 
485, 518 

tolerance: 25, 26, 27, 208, 223, 272, 273, 291, 292, 293, 295, 
296, 485, 518 

water stress 218, 318, 358 

yield: 128, 145, 165, 177, 201, 295, 306, 319, 320, 349, 391, 
507, 510 

Subject: Soil Chemistry 

boron: 40, 373, 512 
salt balance: 52, 484, 513 
salt distribution: 17 
SAR: 43 8 

Subject: Soil Management 

land management: 487 

leaching: 31, 33, 58, 61, 66, 205, 209, 240, 243, 246, 249, 284, 
389, 439, 440, 442, 484, 513 

leaching requirement: 31 

soil management: 479 

Subject: Soil Types 

saline soil: 61, 442, 498 

Subject: Soil Water 

groundwater: 13, 34, 49, 54, 130, 175, 198, 258, 308, 414, 440, 
441, 466 

hydro: 11, 88, 212, 316, 345, 361, 402 



B- 6 



infiltrat: 336, 347 
perched: 502 

return flow: 11, 44, 46, 211, 235, 259, 260, 266, 275, 276, 277, 
278, 279, 471, 473, 474, 475, 476, 486 

soil water: 113, 114, 214, 420, 453, 511 

water table: 16, 102, 165, 179, 194, 261, 268, 269, 306, 327, 
437, 502 



Subject: Treatment 

evaporation pond: 443 
phreatophyte : 330, 331 
treatment: 67, 307 

Subject: Water Distribution 

seepage: 142 

canal: 399, 457, 463 

water distribution: 267 

water tables: 16, 102, 165, 179, 194, 261, 268, 269, 306, 327, 
437, 502 

Subject: Water Quality 

brackish: 348, 349, 370 

environment: 72, 151, 271, 336, 374, 412, 494 

inorganic: 130 

organic: 130, 364 

pollutant: 343 

selenium: 9, 22, 72, 130, 224, 271, 362, 428, 454 

sodium: 131 

trace elements: 271 



B- 7 



water quality: 19, 20, 28, 56, 63, 75, 76, 107, 234, 235, 279, 
321, 336, 345, 414, 415, 440, 470, 482, 503, 508 



Subject: Water Type 

drainage water: 31 

irrigation water: 28, 38, 58, 107, 108, 197, 220, 227, 242, 246, 
281, 299, 321, 334, 370, 376, 389, 397, 419, 421, 434, 464, 
467, 508 

saline water: 2, 17, 32, 141, 176, 244, 245, 268, 269, 298, 383, 
384, 385, 386, 427 

surface water: 49, 127 

waste water: 27, 56, 62, 109, 136, 137, 138, 188, 287, 307, 337, 
344, 415, 416 



_!/ Numbers refer to bibliographic references summarized in 
Appendix A. 



B- 8 



APPENDIX C 



DIRECTORY OF RESEARCH PERSONNEL 



DIRECTORY OF RESEARCH PERSONNEL DOING WORK RELATED TO 
ON-FARM AGRICULTURAL MANAGEMENT ALTERNATIVES 



AMUNDSON, Ronald (415) 642-3005 

Assistant Professor 

Plant and Soil Biology 

University of California 

Hilgard Hall 

Berkeley, California 94720 

USA 

AYARS, James E. (209) 251-0437 

Agricultural Engineer 

Water Management Research Laboratory 

U. S. D. A. Agricultural Research Service 

2021 S. Peach Ave. 

Fresno, California 93727 

USA 

BACKLUND, Virgil C. (916) 449-2819 

U. S. D. A. Soil Conservation Service 
2828 Chiles Road 
Davis, California 95616 

USA 

BECK, Louis (209) 445-5443 

San Joaquin District 

Department of Water Resources 

3374 East Shields Ave. 

Fresno, California 93726 

USA 

BERRINGER, Dave (916) 322-4503 

Division of Water Rights 

State Water Resources Control Board 

901 "P" Street 

Sacramento, California 95814 

USA 

BERTOLDI, Gilbert L. (916) 978-4633 

District Chief 

Water Resources Division, Room W-2235 

U. S. Geological Survey 

2800 Cottage Way 

Sacramento, California 95825 

USA 

BEYER, John (209) 487-5223 

U. S. Soil Conservation Service 

1130 "0" Street 

Fresno, California 93721 

USA 

C- 1 



BIELORAI, H. 

Irrigation Scientist 

Institute of Soils and Water, ARO 

The Volcani Center 

P. O. Box 6 

Bet-Dagan 50-250, 

Israel 

BIGGAR, James (916) 752-0681 

Professor 

Land, Air and Water Resources 

University of California 

Veihmeyer Hall 

Davis, California 95616 

USA 

BINGHAM, Frank T. (714) 787-5108 

Professor 

Soil and Environmental Sciences 

University of California 

Pierce Hall 

Riverside, California 92521 

USA 

BOUWER, Herman (602) 261-4356 

Director 

Water Conservation Research Laboratory 

U.S.D.A, Agricultural Research Service 

4331 E. Broadway 

Phoenix, Arizona 85040 

USA 

BOWMAN, Robert S. (602) 261-4356 

Water Conservation Research Laboratory 

U. S. D. A. Agricultural Research Service 

4331 East Broadway Road 

Phoenix, Arizona 85040 

USA 

BRESLER, Eshel 

Agricultural Research Organization 

The Volcani Center 

P.O. Box 6 

Bet-Dagan, 

Israel 

BROOKS, William H. (916) 449-2816 

Watershed Planning Staff 

U. S. D. A. Soil Conservation Service 

2828 Chiles Road 

Davis, California 95616 

USA 



C- 2 



BURAU; Richard G. (916) 752-0194 

Professor 

Land, Air and Water Resources 

University of California 

Hoagland Hall 

DaviS/ California 95616 

USA 

BUTCHERT, Jerald (209) 224-1523 

Westlands Water District 

3130 N. Fresno St. 

Fresno, California 93703 

USA 

BUTTERFIELD, Suzanne (916) 323-4806 

Chief 

Office of Water Conservation 

California Department of Water Resources 

P. O. Box 388 

Sacramento, California 95802 

USA 

CERVINKA, Vashek (Ph.D.) (916) 445-6719 

Research Manager 

Agricultural Resources Branch 

California Department of Food and Agriculture 

1220 "N" St. 

Sacramento, California 95814 

USA 

CHANG, Andrew C. (714) 787-5325 

Professor 

Soil and Environmental Sciences 

University of California 

Pierce Hall 

Riverside, California 92521 

USA 

CHAUDHARY, T. N . 

Associate Professor 

Department of Soils 

Punjab Agricultural University 

Ludhiana , 

India 

CRADDOCK, Ed (916) 445-9958 

Chief /Agricultural Water Conservation Branch 

Office of Water Conservation 

California Department of Water Resources 

P. O. Box 388 

Sacramento, California 95802 

USA 



C- 3 



DAVENPORT, David C. 

Associate Professor 

Land, Air and Water Resources 

University of California 

Viehmeyer Hall 

Davis, California 95616 

USA 



(916) 752-2360 



DAVIS, K. R. 

Soil Scientist 

Water Management Research Laboratory 

U. S. D. A. Agricultural Research Service 

2021 S. Peach Ave. 

Fresno, California 93727 

USA 



(209) 251-0437 



DEDRICK, Allen R, 

Agricultural Engineer 

Water Conservation Research Laboratory 

U. S. D. A. Agricultural Research Service 

4331 East Broadway Road 

Phoenix, Arizona 85040 

USA 



(602) 261-4356 



DEVEREL, Steve 

Water Resources Division, 

U. S. Geological Survey 

2800 Cottage Way 

Sacramento, California 95825 

USA 



(916) 978-4606 
Room W-2235, Federal Building 



EPSTEIN, Emanuel 

Professor 

Land, Air and Water Resources 

University of California 

Hoagland Hall 

Davis, California 95616 

USA 



916) 752-0197 



FERERES, E. 

Extension Irrigationist 

Dept. of Land, Air and Water Resources 

University of California 

Davis, California 95616 

USA 



(916) 752-0457 



FERRY, George 

Director 

Kings County Cooperative Extension 

310 Campus Drive 

Hanford, California 93230 

USA 



(209) 582-3211 



C- 4 



FRANCOIS, L. E. (714) 683-0170 

U. S. Salinity Laboratory 

U. S. D. A. Agricultural Research Service 

4500 Glenwood Drive 

Riverside, California 92501 

USA 

FRY, Robert A. (209) 584-9209 

Resource Conservationist 

U. S. D. A. Soil Conservation Service 

Hanford, California 

USA 

GILLIOM, Robert J. (916) 978-4633 

Chief 

Western San Joaquin Valley Hydrological Studies Unit 

Water Resources Division, U. S. Geological Survey 

2800 Cottage Way 

Sacramento, California 95825 

USA 

GOLDHAMER, David A. (209) 646-2794 

Area Soils & Irrigation Specialist 

Cooperative Extension, Kearney Agricultural Center 

University of California 

9240 S. Riverbend Ave. 

Parlier, California 93648 

USA 

GRATTEN, Stephen R. (916) 752-1130 

Extension Plant Water Specialist 

Cooperative Extension 

University of California 

Veihmeyer Hall 

Davis, California 95616 

USA 

GRIMES, Donald W. (209) 646-2794 

Water Scientist 

Cooperative Extension, Kearney Agricultural Center 

University of California 

9240 S. Riverbend Ave. 

Parlier, California 93648 

USA 

GUITJENS, J. C. (702) 784-6947 

Department of Plant Science 

University of Nevada-Reno 

Reno, Nevada 89557-0004 

USA 



C- 5 



GULATI, Om (916) 324-5630 

Division of Water Rights 

State Water Resources Control Board 

901 "P" Street 

Sacramento/ California 95814 

USA 

HAGAN, Robert M. (916) 752-0457 

Professor 

Land, Air and Water Resources 

University of California 

Veihmeyer Hall 

DaviS/ California 95616 

USA 

HAMBLETON, William (209) 488-3285 

Director 

Fresno County Cooperative Extension 

1720 South Maple Ave. 

Fresno/ California 93702 

USA 

HANSEN, Henry L,, P.E. (916) 978-4974 

Civil Engineer 

U. S. Bureau of Reclamation 

2800 Cottage Way 

Sacramento, California 95825 

USA 

HANSON, Blaine (916) 752-1130 

Irrigation and Drainage Specialist 

Cooperative Extension 

University of California 

Veihmeyer Hall 

Davis, California 95616 

USA 

HEERMANN, Dale F. (303) 491-8511 

Agricultural Engineer 

Agricultural Research 

U. S. Department of Agriculture - Science and Education 

Fort Collins, Colorado 80523 

USA 

HOFFMAN, Glenn J. (209) 251-0437 

Research Leader 

Water Management Research Laboratory 

U. S. D. A. Agricultural Research Service 

2021 S. Peach Avenue 

Fresno, California 93727 

USA 



C- 6 



HORNER, Gerald L. 

Agricultural Economist 

Agricultural Economics 

U. S. D. A. - E. R. S. 

Voorhies Hall 

Davis, California 95616 

USA 



(916) 752-6001 



HULSMAN, Robert B. 

Department of Agricultural Engineering 

New Mexico State University 

P. 0. Box 3268 

Las Cruces, New Mexico 88003 

USA 

IMHOFF, Ed 

San Joaquin Drainage Program 

U.S. Bureau of Reclamation 

2800 Cottage Way 

Sacramento, CA 95825 

USA 

JARRELL, Wesley M. 

Associate Professor 

Soil and Environmental Sciences 

University of California 

Geology Building 

Riverside, California 92521 

USA 

JOHNS, Jerry 

Division of Water Rights 

State Water Resources Control Board 

901 "P" Street 

Sacramanto, California 95814 

USA 

JOHNSON, Dan 

Salinity and Drainage Specialist 

U. S. D. A. Soil Conservation Service 

1130 "0" Street 

Fresno, California 93721 

USA 

JOHNSTON, William R. 

Assistant Manager-Chief of Operations 

Westlands Water District 

3130 N. Fresno St. 

Fresno, California 93726 

USA 



(505) 646-3007 



(916) 978-4948 



(714) 787-3785 



(916) 322-4503 



(209) 487-5125 



(209) 224-1523 



C- 7 



JURY, William A. 

Professor 

Soil and Environmental Sciences 

University of California 

Geology Building 

Riverside/ California 92521 

USA 



(714) 787-5134 



KNAPP, Keith C. 

Assistant Professor 

Soil and Environmental Sciences 

University of California 

Geology Building 

Riverside, California 92521 

USA 



(714) 787-4195 



KRUSE, E. G. 

Agricultural Engineer 

U. S. D. A. Agricultural Research Service 

Fort Collins, Colorado 

USA 



(303) 491-8511 



LAUCHLI, Andre 

Professor and Chair 

Land, Air and Water Resources 

University of California 

Hoagland Hall 

Davis, California 95616 

USA 



(916) 752-1450 



LAW, James P., Jr. (405) 332-8800 

Chief 

Irrigated Agriculture Section, Robert S. Kerr, Environmental 

U. S. Environmental Protection Agency 

P. 0. Box 1198 

Ada, Oklahoma 74820 

USA 



LEE, Edwin W. (Ph.D. ) 
Supervisory Sanitary Engineer 
San Joaquin Drainage Program 
U. S. Bureau of Reclamation 
2800 Cottage Way 
Sacramento, California 95825 
USA 



(916) 978-4948 



LETEY, John 

Professor 

Soil and Environmental Sciences 

University of California 

Geology Building 

Riverside, California 92521 

USA 



(714) 787-5105 



C- 8 



LYFORD, Gordon R. 

Agricultural Engineer 

U. S. Bureau of Reclamation 

2800 Cottage Way 

Sacramento/ California 95825 

USA 



(916) 484-4389 



LYNN, Curtis 

Director 

Tulare County Cooperative Extension 

Woodland Dr. and W. Main 

Visalis, California 93291 

USA 



(209) 733-6363 



MAAS, Eugene V. 

U. S. Salinity Laboratory 

U. S. D. A. Agricultural Research Service 

4500 Glenwood Drive 

Riverside, California 92501 

USA 



(714) 683-0170 



MacGILLIVRAY, Norman A. 

Land and Water Use Analyst 

California Department of Water Resources 

Bakersfield, California 

USA 



(805) 395-2815 



MALCOLM, C. V. 

Jarrah Road 

South Perth, 6151, West 

Austral ia 



(09) 367-0111 



Australia 



MARINO, Miguel A. 

Professor, Civil Engineering 

Dept. of Land, Air and Water Resources 

University of California 

Veihmeyer Hall 

Davis, California 95616 

USA 



(916) 752-0684 



MAY, Donald 

Fresno County Cooperative Extension 

1720 South Maple Ave. 

Fresno, California 93702 

USA 



(209) 488-3285 



MERRIAM, John L. 

Professor 

Agricultural Engineering Department 

California Polytechnic State University 

San Luis Obispo, California 

USA 



(805) 832-1111 



C- 9 



MEYER, Roland D. (916) 752-2531 

Extension Soils Specialist 

Cooperative Extension 

University of California 

Hoagland Hall 

Davis, California 95616 

USA 

MEYER, Jewell L. (714) 787-5101 

Irrigation Specialist 

Cooperative Extension 

University of California 

Geology Building 

Riverside, California 92521 

USA ' 

MIYAMOTO, S. (915) 859-9111 

Associate Professor 

Agricultural Research Center 

Texas A & M University 

1380 A & M Circle 

El Paso, Texas 79927 

USA 

NAMKIN, L. N. (512) 968-3392 

Research Soil Scientist 

Soil and Water Conservation Research Division 

U. S. D. A. Agricultural Research Service 

Weslaco, Texas 

USA 

NIELSEN, Donald R. (916) 752-0695 

Professor 

Land, Air and Water Resources 

University of California 

Veihmeyer Hall 

Davis, California 95616 

USA 

NYE, Ronald (805) 964-3278 

175 Kinman Ave #7 
Goleta, California 93117 
USA 

O'NEILL, Titn (209) 826-3084 

Farm Manager 

Bowles Farming Company 

11609 S. Hereford Road 

Los Banos, California 93635 

USA 



C- 10 



OSTER, James D. (714) 787-5100 

Extension Soils and Water Specialist 

Soil and Environmental Sciences 

University of California 

Geology Building 

Riverside, California 92521 

USA 

PHENE, Claude J. (209) 251-0437 

Soil Scientist 

Water Management Research Laboratory 

U. S. D. A. Agricultural Research Service 

2021 S. Peach Avenue 

Fresno, California 93727 

USA 

PLAUT, Z. 

Institute of Soils and Water, ARO 

The Volcani Center 

P. 0. Box 6 

Bet-Dagan , 

Israel 

POST, Steven E. C. (714) 787-5115 

Irrigation and Soil Specialist 

Cooperative Extension 

University of California 

Geology Building 

Riverside, California 92521 

USA 

PRICHARD, Terry (209) 944-3711 

Area Soil and Water Specialist 

Cooperative Extension 

University of California 

420 S. Wilson Way 

Stockton, California 95205 

USA 

RHOADES, James D. (714) 683-0170 

Adjunct Professor-Research Leader 

U. S. Salinity Laboratory 

U. S. D. A. Agricultural Research Service 

4500 Glenwood Drive 

Riverside, California 92501 

USA 

ROLSTON, Dennis E. (916) 752-2113 

Professor 

Land, Air and Water Resources 

University of California 

Hoagland Hall 

Davis, California 95616 

USA 



C- 11 



SACHS, Roy 

Dept. of Environmental Horticulture 

University of California 

DaviS/ California 95616 

USA 



(916) 752-3071 



SCHONEMAN, Richard A. 

Agricultural Engineer 

Water Management Research Laboratory 

U. S. D. A. Agricultural Research Service 

2021 S. Peach Ave. 

Fresno/ California 93727 

USA 



(209) 251-0437 



SHAINBERG, I. 

Institute of Soils and Water, ARC 

The Volcani Center 

P. 0. Box 6 

Bet-Dagan , 

Israel 



SHALHEVET, Joseph 

Director 

Institute of Soils and Water, ARO 

The Volcani Center 

P. O. Box 6 

Bet-Dagan , 

Israel 



(02) 940272 



SHAVER, John 

California Agricultural Technology Institute 

California State University Fresno 

N. Maple Ave. & E. Shaw Ave. 

Fresno, California 93740-0079 

USA 



(209) 294-2361 



SINGER, Michael J. 

Associate Professor 

Land, Air and Water Resources 

University of California 

Hoagland Hall 

Davis, California 95616 

USA 



(916) 752-1406 



SMITH, Felix 

2787 Del Monte Street 

West Sacramento, California 95691 

USA 



(916) 478-4877 



C- 12 



SNYDER, J. Herbert (916) 752-1544 

Professor, Director, Water Resources Center 

Agricultural Economics 

University of California 

Wickson Hall 

Davis, California 95616 

USA 

SOLOMAN, Ken (209) 294-2066 

Director 

Center for Irrigation Technology 

California State University - Fresno 

Fresno, California 93710 

USA 

STANDIFORD, Rich (415) 642-2360 

U. C. Cooperative Extension Forestry 

University of California 

Mulford Hall 

Berkeley, California 94720 

USA 

STEINERT, Byron C. (209) 224-1523 

Senior Engineer 

Westlands Water District 

3130 North Fresno St. 

Fresno, California 93703 

USA 

STEPHENS, Larry D. (303) 234-3006 

Executive Vice President 

U. S. Committee on Irrigation and Drainage 

P. 0. Box 15326 

Denver, Colorado 80215 

USA 

SWAIN, Don (916) 978-4971 

San Joaquin Drainage Program 

U.S. Bureau of Reclamation 

Mid-Pacific Region 

2800 Cottage Way 

Sacramento, CA 95825 

USA 

SWAIN, Walter C. (916) 978-4648 

Hydologist 

Water Resources Division 

U. S. Geological Survey 

2800 Cottage Way 

Sacramento, California 95825 

USA 



C- 13 



TAMBLYN, Thomas A. (916) 322-9760 

Assoc. Water Resource Control Engineer 

Division of Water Rights/ Bay-Delta Program 

State Water Resources Control Board 

901 "P" Street 

Sacramento; California 95810 

USA 

TANJI, Kenneth K. (916) 752-0683 

Professor 

Land/ Air and Water Resources 

University of California 

Veihmeyer Hall 

Davis/ California 95616 

USA 

TISCHER, Jim (209) 655-3004 

Consultant 

Community Alliance for Responsible Water Policy 

P. O. Box 208 

Mendota, California 93640 

USA 

WALLACE/ L. T. (415) 642-5495 

Extension Economist 

Cooperative Extension - Agricultural Economics 

University of California 

Giannini Hall 

Berkeley/ California 94720 

USA 

WESTCOT, Dennis (916) 322-1611 

Central Valley Region 

State Water Quality Control Board 

3201 "S" Street 

Sacramento/ California 95814 

USA 

WILDMAN/ William E. (916) 752-2532 

Professor 

Cooperative Extension 

University of California 

Hoagland Hall 

Davis/ California 95616 

USA 

WILLARDSON, Lyman S. (801) 750-2785 

Professor 

Dept. of Agricultural and Irrigation Engineering 

Utah State University 

UMC 41 

Logan, Utah 84322 

USA 



C- 14 



WILLEY, Zack 

Environmental Defense Fund 
2606 Dwight Way 
Berkeley, California 94704 
USA 



(415) 548-8906 



YARON, Bruno 

Director 

Institute of Soils and Water, ARO 

The Volcani Center 

P. 0. Box 6 

Bet-Dagan, 50250 

Israel 



03-980272,980111 



C- 15 



APPENDIX D 
ON-FARM AGRICULTURAL MANAGEMENT GROWER SURVEY 



CONFIDENTIAL CONFIDENTIAL 

ON-FARM AGRICULTURAL MANAGEMENT GROWER SURVEY 



Survey No.: Date Completed: 


1. Ranch Name: 


2. Ranch Location: Township Range 


Sect ion ( s ) : 


3. Irrigated Acreage: 


Do you own the Ranch property: 

Lease : 
Manage : 


Yes No 
Yes No 
Yes No 



4. Is the ranch property located in a water district? 
Yes No 

Acreage 



Name of District(s): 



Current crop production: 

Avg . Ann , 
Acreage 
(last 5 

Type of Crop Years ) 



Average 
Annual Yield Average Annual 
(last 5 Years) Water Appl.(ac/in) 



Source of Information: 



Average Annual Yield: 



Average Annual Water 
Application : 



D- 1 



6. Source, Amount and Cost of Water Delivery: 

Source Annual Del i very ( ac-ft ) Cost ( $ ) /ac-f t 



Is irrigation water available on demand or is it delivered 
according to a set rotation/schedule? 

Demand Schedule 

When is irrigation water available from the water district? 

Available all year: Yes No 

1st date available 

Last date available 

What are the water delivery capabilities of the irrigation 
district to your ranch property? 

Times per month 

Duration of flows 

Flow volume 

Average Water Salinity 



Electrical 
Conductivity 
(Micromhs ) 



10. If irrigation water was available year round would you 
change your irrigation schedule? 



Yes 



No 



If yes, how would you change? 



11. What type of on-farm water delivery facilities do you have? 

Pipeline: % of area served: 

L ined ditch: 
Unl ined ditch: 



% of area served: 
% of area served: 



D- 2 



12. What types of irrigation systems do you use? (ie, sprinkler, 
flood/furrow, drip/trickle, etc.) 



Crop 



1985 
Acreage 



Type of 
System 



13. Do you have records of your annual on-farm irrigation water 
application cost? (i.e. capital/interest/ operation & 
maintenance, energy, labor, etc.) 



Yes 



No 



14. Do you think your present irrigation practices could be 
improved? 

Yes No 

If yes, explain what on-farm management changes could be 
implemented. 



15. Do you contemplate implementing these changes? 
Yes No If yes, when: 



D- 3 



16. Do you have an irrigation scheduling program? 

Yes No 

If yes, technique used: 



If yeS; is the work performed by ranch personnel or a 
professional consultant? 
Ranch personnel 



Consultant 
Other 



Describe : 



17. Do you have records of your annual irrigation schedule? 
Yes No 

18. Do you have a tailwater recovery/reuse system? Yes No 

If no I do you anticipate installing one? Yes No 

If yes, what percentage of your irrigation water application 
is met by tailwater reuse? 



How did you calculate the percentage of tailwater reuse? 



19. Is the ranch property located in a drainage district? 
Yes No 

Acreage 



Name of District(s): 



D- 4 



20. Do you have existing infield subsurface drainage facilities? 

Yes No 

If yes: SCS soil series 

Tile depth 

Tile spacing 



Acreage drained 
Installation cost ($/ac) 



Date: 
Date: 
Date: 



Annual drainage flow (ac-ft 



Source of drainage flow estimate: 



Method of drain water disposal 
Average drainwater salinity 



Average drainwater sodium adsorption ratio 

Benefit of Drains: 

Magnitude of water table elevation reduction 



How much has soil chemistry been improved 



How much has crop yield been increased 



D- 5 



If no: Do you have acreage presently requiring drainage? 

Yes No 

Acreage requiring drainage: Source of Information 

Water Table Depth: Source of Information 

Estimated Existing 

% Yield Reduction Source of Information 



By Crop : 



21. Do you anticipate installing infield subsurface drainage 
facilities in the future? 



Yes No 



If yes; when: 



22. Do you presently have an on-farm subsurface drainage water 
disposal system? (ie, evaporation ponds, etc.) 

Yes No 



If yes, type of system 



If no, do you anticipate installing an on-farm subsurface 
drainage water disposal system? Yes No 

23. Why did you select the on-farm subsurface drainage water 
disposal system you now have (cost, convenience, no other 
outlet , etc . ) 



24. Do you reuse subsurface drainage flows for irrigation? 

Yes No 

If yes, is this water: 

Used w/o blending , Salinity , electrical 

conductivity 
(micromhs ) 

Blended with groundwater , Salinity 



Blended with surface water , Salinity 

Blended with tailwater , Salinity 



D- 6 



25. Is subsurface drainwater used for irrigation applied during 
any specific crop growth stage(s)? 



Yes 



No 



If yes, what crop growth stages? 
Crop Growth Stage 



26. Is part of the crop water requirement at your ranch provided 
by plant uptake from a shallow perched water table? 



Yes 



No 



If yes, what crops are planted to use this water? 
Crop Approximate Acreage 



27. Do you follow a regular crop rotation? 

Yes No 

If yes, on what factors is your rotation based 

Market : 

Soil Salinity:^ , 



Subsurface Drainage problems:_ 
Irrigation water availibil ity_ 



D- 7 



Other: 



Describe 



28. Have you tried growing any different crops in the past that 
you are not growing now? 



Crop 



Acres 



Reason Stopped 



29. Do you have any specific suggestions for on-farm management 
techniques that could be implemented to reduce subsurface 
drainage water flows or improve drainage water quality? 



30. What is presently restricting the implementation of these 
techniques in your operation? (from question 29) 



D- 8 



31. What existing or proposed institutional regulations or 

economic disincentives prevent you from implementing on-farm 
management techniques which would reduce subsurface drainage 
water flows or improve drainage water quality. 



GK)-785-055-'^58l9 D- 9